BACKGROUND OF THE INVENTION Surfactant-containing compositions have many forms inter alia granules, particles, bars, liquids, creams, gels, and pastes. It is possible to prepare clear and/or translucent liquids, creams, gels, and pastes containing sulfated surfactants and to suitably color or dye the compositions to match the aesthetic desires of the consumer. However, these compositions suffer from the fact that they begin to develop a yellow color or cast after storage caused by degradation of the ingredients delivered to the composition via sulfated or sulfonated surfactants. This yellow cast or color development has a direct and pejorative effect on the product formulatability. For example, a clear product which has been colored blue by the formulator gradually becomes green in color with the onset to of the development of a yellow cast. In addition, clear water-white compositions appear yellow to brown upon standing. Therefore, this persistent development of off-color due to the instability of the source of sulfated surfactants has limited the range of colors and embodiments which formulators may provide to the consumer.

At present, crude sulfonated or sulfated surfactant pastes are treated with hydrogen peroxide at a pH above about 5. Once formulated, unless precautions are taken, these surfactants lead to the development of unwanted color in clear embodiments. Currently the only existing remedy for this unwanted color development is the inclusion of color mediating agents, i. e., chelants and bleaches, into the final formula. In addition, the formulator is required to hold the crude surfactant paste in contact with hydrogen peroxide for a period of from about 24 to about 48 hours in order to achieve even a transitory colorless product.

Accordingly, there remains a need in the art for a process for preparing sulfated surfactants which when formulated into a surfactant-containing composition, does not promote the development of unwanted color. In addition, there is a need for a process in

which the crude surfactant paste can be immediately used to formulate sulfate and sulfonate containing compositions.

BACKGROUND ART The following relate to the preparation of stable, colorless detergent compositions containing anionic and/or nonionic surfactants. U. S. 5,244,593, Roselle et al., issued September 14,1993.

SUMMARY OF THE INVENTION The present invention meets the aforementioned needs in that it has been surprisingly discovered that a surfactant paste derived from the sulfation or sulfonation product of alcohols can be provided which when formulated into surfactant-containing compositions does not promote the formation of unwanted color or yellow casts. The surfactant pastes obtained by the process of the present invention can be suitably used to prepare inter alia clear, water-white, translucent light duty liquid cleaning compositions, heavy duty laundry detergent compositions, laundry bars, and colored embodiments thereof. The non-yellowing and non-color producing surfactant pastes of the present invention can be manufactured by treating a surfactant acid mix with a source of hydrogen peroxide at a pH of from about 0.1 to about 5, preferably from 0.1 to about 4, more preferably from 0.1 to about 3, most preferably from about 0.4 to about 2, followed by a neutralization step.

It has been further surprisingly discovered that the decolorizing treatment of crude sulfate and sulfonate acidic pastes at a pH of from about 0.1 to about 5 with hydrogen peroxide is so rapid and complete that the current need to allow for long contact times (24- 48 hours) between the crude pastes and hydrogen peroxide has been eliminated. By the process of the present invention, as quickly as the crude sulfonate and sulfate are produced, the materials can be formulated into surfactant containing products.

In its most basic form, the present invention comprises the steps of : a) providing a source of an acidic surfactant mixture; b) admixing said source of acidic surfactant mixture and a source of hydrogen peroxide to form a bleached acidic surfactant admixture; and c) neutralizing said acidic bleached admixture to form a neutralized surfactant paste.

The present invention further relates to the composition and form of the source of hydrogen peroxide as well as the temperature at which each step of the process is conducted. The present invention also relates to the suitability of the present process in that it is adaptable to either batch or continuous manufacturing processes. The present invention further relates to the formation of sulfate or sulfonate containing pastes which can be directly added to other detergent ingredients or adjuncts without the costly need to add

color mediators such as bleaches and metal chelants. These and other objects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims.

All percentages, ratios and proportions herein are by weight, unless otherwise specified. All temperatures are in degrees Celsius (° C) unless otherwise specified. All documents cited are in relevant part, incorporated herein by reference.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for preparing a surfactant paste, said surfactant paste suitable for use in formulating sulfated or sulfonate surfactant containing compositions, especially compositions wherein a clear or water white and non-yellowing or non-color forming composition is desired. For example, light duty liquid cleaning compositions can be can be formulated which are clear and colorless and which remain clear and colorless. The surfactant paste of the present invention is also suitable for use in compositions wherein the presence of yellowing or the development of color has an adverse effect on the product color. For example, a heavy duty liquid detergent which is formulated to have an aesthetically desirable blue color will have its color shift to a"green"shade if yellow color bodies develop upon standing. However, the sulfated or sulfonated surfactant pastes are not limited for use in liquid or clear detergent compositions.

Surprisingly the present invention eliminates the need for the presence of bleaching agents, chelants, or the like to be added to the final product formulation to eliminate the development of unwanted yellowing or other off colors. The process of the present invention allows the formulator the widest possible options when admixing other surfactants or adjunct ingredients into the formula since the compatibility of said adjuncts (i. e., colorants, perfumes) with color mediators (i. e. bleaches, chelants) must no longer be considered.

The present invention comprises the following elements, steps, and procedures.

Step (a): Providing a Source of an Acidic Surfactant Mixture The first step in the process of the present invention is to provide a source of one or more surfactants which has a pH from about 0.1 to about 5, preferably from 0.4 to about 4, more preferably from 0.1 to about 3, most preferably from about 0.1 to about 2. Said source can comprise only surfactants which are to be used in the final light duty liquid cleaning composition or the source can include other carriers or adjunct ingredients which are compatible with the present process including other surfactants, especially nonionic surfactants.

Preferred surfactants which are presented in Step (a) as sources of Acidic Surfactant Mixtures are aliphatic alcohols, aromatic alcohols, aliphatic or aromatic alkoxylated alcohols (preferably ethoxylated), and mixtures thereof which have been

sulfated or sulfonated, and mixtures of the sulfonated or sulfated alcohols and non-sulfated or non-sulfonated alcohols. For example, a C I 4-C 15 alcohol ethoxylate having an average of 2.25 ethoxylates per molecule is sulfated by an acidic process (i. e. Falling Film Reactor, etc.), then admixed with an additional amount of non-sulfated C 1 4-C1 5 alcohol ethoxylate having an average of 2.25 ethoxylates per molecule. This admixture of sulfated and non- sulfated alkyl ethoxylate is a suitable source of raw acidic sulfates which can be subsequently carried into Step (b) of the present process. However, the C14-C15 alcohol ethoxylate having an average of 2.25 ethoxylates per molecule which has been sulfated and has a pH of from 0.1 to about 5 is also suitable for use as a sources of raw acidic surfactant an non-sulfated surfactant need not be added. In addition, more than one type of sulfated, sulfonated, non-sulfated, or non-sulfonated surfactant may be carried into Step (b) of the present process as long as the pH requirements described herein are met.

In a further embodiment described further herein below, the formulator may wish not to add an amount of non-sulfated or sulfonated surfactant to the raw acidic mixture.

Instead, a mixture of non-sulfated/non-sulfonated surfactant and sulfated/sulfonated surfactant can be formed by the addition of water wherein an amount of sulfated/sulfonated surfactant is reverted back to the non-sulfated/sulfonated form.

An example of a surfactant source includes the raw acidic sulfates which are obtained by sulfation of fatty alcohols in a Falling Film Reactor (FFR) wherein S03 is contacted with a mixture of fatty alcohols under an inert atmosphere. The acidic surfactant mixture obtained from the FFR comprises a mixture of sulfated and non-sulfated alcohols.

Batch reactions which provide sulfated alcohols are also suitable for use in the present invention. However, any source of surfactant, for example sulfated linear alkyl phenols (HLAS), is suitable for use in the process of the present invention provided that the pH of the solution is from about 0.1 to about 5.

Step (b): Admixing a Source of Hydrogen Peroxide with an Acidic Surfactant Mixture The second step of the process of the present invention comprises admixing a source of hydrogen peroxide with the acidic surfactant mixture provided in step (a).

Sources of hydrogen peroxide suitable for use in the present invention include aqueous solutions of hydrogen peroxide, for example, 30%, 50%, 70% and 90% hydrogen peroxide.

The present invention may also include the use of a pre-mix. In this case a pre-mix which contains a source of hydrogen peroxide is added to the Acidic Surfactant Mixture. In forming the pre-mix, typically the source of hydrogen peroxide is admixed with one or more compatible carriers or other ingredients. Suitable solvents and carriers are selected from the group consisting Of C I-C22 linear or branched alcohols, C2-C22 linear or branched alkyl ethoxy alcohols, C2-C22 glycols, and mixtures thereof. It is desired to minimize the amount of water present during Step (b) of the present invention in order to

prevent or minimize reversion of the sulfated feedstock back to the un-sulfated alcohol.

However, a formulator wishing to prepare a final surfactant paste which contains some amount of un-sulfated alcohol may choose to inject water into the present process to insure some degree of reversion.

Typically pre-mixes comprise, depending upon the amount of water contained in the source of hydrogen peroxide, from about 5% to about 10% water and from about 80% to about 90% carrier. Preferred carriers include ethanol, propylene glycol, as well as non- ionic surfactants.

The source of hydrogen peroxide must be brought into contact and efficiently admixed with the acidic surfactant mixture at a pH of from about 0.1 to about 5. Without wishing to be limited by theory, when the source of hydrogen peroxide contacts the acidic surfactant mixture within the pH range of from about 0.1 to about 5, the hydrogen peroxide is believed to be converted to the free radical species,-OH. By contrast, if the pH of the acidic surfactant mixture is sufficiently greater than about 5, this can result in the formation of the peroxide anion,-OOH, which is a less effective bleaching species. Preferably the hydrogen peroxide remains in contact with the acidic surfactant mixture for sufficient time to affect the desired color reduction.

Step (b) may be conducted at any temperature which is sufficient to provide a sulfate or sulfonate paste suitable for formulating a clear, non-color forming composition.

Preferably the Step (b) is conducted at a temperature of at least about 15° C, more preferably at least about 25° C, most preferably at least about 30° C to about 100° C, more preferably about 85° C, most preferably at least about 70° C. However, as described herein below, any temperature which insures a Transmittance at 470 nm of at least about 60% at a temperature of from about 20° C to about 70° C is sufficient for producing the sulfate or sulfonate surfactants of the present invention.

Longer contact times between the acidic surfactant mixture and hydrogen peroxide results in lower color levels, but with longer contact times some sulfated materials will have a propensity to revert back to the alcohol form depending upon the amount of moisture present. However, if some non-sulfated alcohols are desired in the final sulfated surfactant mixture, the neutralization step can be delayed to allow for reversion. In addition, depending upon the type of sulfated alcohol which is being prepared, neutralization can be considerably delayed without fear of severe reversion. For example, linear alkyl benzene sulfonates (HLAS) pastes which have not been neutralized may be suitably shipped at low pH with hydrogen peroxide present and then neutralized at a later time when needed.

Step (c): Neutralization

The final step of the process of the present invention is neutralizing the acidic bleaching admixture to form a stable surfactant paste. The neutralization can be accomplished by adding a sufficient amount of alkaline material inter alia sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium, hydroxide, magnesium hydroxide, ammonium hydroxide. The final pH of the surfactant paste can range from about 5 to about 13 depending upon the type of liquid light duty cleaning composition which is to be formulated using the surfactant paste.

Preferably the final surfactant paste has less than 0.002% by weight, of residual peroxide, more preferably the final surfactant paste comprises no residual peroxide.

For processes which utilize a pre-mix composition comprising hydrogen peroxide, a preferred pre-mix composition comprises: i) from about 5% to about 10% by weight, of hydrogen peroxide; ii) from about 5% to about 10% by weight, of water; and ii) from about 80% to about 90% by weight, of a solvent selected from the group consisting of C1-C22 alkyl alcohol, C2-C22 alkyl ethoxy alcohol, C2-C22 glycol, and mixtures thereof; wherein said pre-mix is added to the acidic surfactant mixture in Step (b).

The process of the present invention is suitable for use in preparing any composition which comprises a sulfated or sulfonated surfactant. Non-limiting examples of both clear, translucent, colorless embodiments as well as other embodiments are listed herein below.

Light Duty Liquid Compositions The following are examples of Light Duty Liquid Cleaning compositions which remain water-white when the sulfated surfactants are processed according to the process of the present invention.

TABLE I weight % Ingredients 1 2 3 4 Ammonium C 1 2-C 13 alkyl ethoxy (E1) sulfate 15. 5 15. 5 15.5 15. 5 Ammonium C12-Cl3 alkyl ethoxy (E6.5) 12.0 12.0 12. 0 12. 0 sulfate Sodiumchloride 1. 0 1. 0 1. 0 1.0 Ammonium xylene sulfonate 4.0 4. 0 4. 0 4.0 Ethanol 5. 5 5. 5 5. 5 5.5 Perfume 0. 09 0. 09 0. 09 0.09 Dodecyl dimethyl amine oxide----5. 0 5.0 Citric Acid 0. 1 0.1 Hyrogen peroxide 0. 4 0. 4 0. 4 0.4 Water bal. bal. bal. bal. Final product pH using pH trim 1 7. 1 7. 1 7. 7.1

1. As a 10% solution.

Heavy Duty Liquid Laundrv Detergents The following describe heavy duty liquid detergent compositions according to the present invention: TABLE II weight % Ingredient 5 6 7 8 Polyhydroxy Coco-Fatty Acid Amide 3. 65 3. 50 C12-C13 Alcohol Ethoxylate Eg 3. 65 0. 80 Sodium C12-CI5 Alcohol Sulfate 6. 03 2. 50 Sodium C12-CI5 Alcohol Ethoxylate E2 5 9. 29 15. 10 Sulfate Sodium C14-C15 Alcohol Ethoxylate E2 25----18.00 18.00 Sulfate Alkyl N-Methyl Glucose Amide -- -- 4.50 4.50 Clo Amidopropyl Amine 1. 30 Citric Acid 2. 44 3. 00 3.00 3.00 Fatty Acid (Cl2-Cl4) 4. 23 2.00 2.00 2.00 NEODOL 23-91----2.00 2.00 Ethanol 3. 00 2.81 3.40 3.40 Monoethanolamine 1. 50 0.75 1.00 1.00 Propanediol 8. 00 7.50 7.50 7.00 Boric Acid 3. 50 3.50 3.50 3. 50 Tetraethylenepentamine -- 1.18 -- -- Sodium Toluene Sulfonate 2. 50 2.25 2.50 2.50 NaOH 2. 08 2.43 2.62 2.62 Optical brightener2 1. 60 1.30 0.27 0.27 Soil Release Polymer3 0. 50 0. 50---- Soil Release Polymer4----2.00 1.00 Water5 balance balance balance balance I 1. Eg Ethoxylated Alcohols as sold by the Shell Oil Co.

2.4,4',-bis [ (4-anilino-6- (N-2-bis-hydroxyethyl)-s-triazine-2-yl) amino]-2,2'- stilbenedisulfonic acid.

3. Soil release polymer according to U. S. Patent 4,968,451, Scheibel et al., issued November 6,1990.

4. Soil release polymer according to U. S. Patent 4,702,857, Gosselink, issued October 27, 1987.

5. Balance to 100% can, for example, perfume, suds suppresser, soil dispersant, chelating agents, dye transfer inhibiting agents, additional water, and fillers, including CaC03, talc, silicates, etc.

Heavy Dutv Liquid Laundrv Detergents with Enzymes Because the sulfated surfactant paste produced by the process of the present invention requires no residual peroxide to maintain non-yellow and color free properties, heavy duty liquid laundry detergents with enzymes can be suitably formulated to be clear.

The following are non-limiting examples of HDL's comprising enzymes.

TABLE III <BR> <BR> <BR> <BR> <BR> weight % Ingredient 9 10 11 12 Polyhydroxy Coco-Fatty Acid Amide 2. 50 2. 50 C12-Cl3 Alcohol Ethoxylate Eg 3. 65 0.80 Sodium C 12-C 15 Alcohol Sulfate 6. 03 2.50 Sodium C12-CI5 Alcohol Ethoxylate E1 8 20. 15 20. 15 Sulfate Sodium C14-C15 Alcohol Ethoxylate E2.25----18.00 18.00 Sulfate Alkyl N-Methyl Glucose Amide 4.50 4.50 Clo Amidopropyl Amine 0. 50 0.50 1.30 Citric Acid 2. 44 3. 00 3.00 3.00 Fatty Acid (C12-Cl4) 2.00 2.00 NEODOL 23-91 0. 63 0. 63---- Ethanol 3. 00 2.81 3.40 3.40 Monoethanolamine 1. 50 0.75 1.00 1.00 Propanediol 8. 00 7.50 7.50 7.00 Boric Acid 3. 50 3.50 3.50 3. 50 Ethoxylated tetraethylenepentamine2 0. 50------ Tekaethylenepentamine 1. 18 Sodium Toluene Sulfonate 2. 50 2. 25 2. 50 2.50 NaOH 2. 08 2. 43 2. 62 2.62 Proteaseenzyme3 0. 78 0. 70---- Proteaseenzyme4----0. 88-- ALCALASE5 ; 1.00 1 Soil Release Polymer6 1. 50 1. 50 2. 00 2.00 Water7 balance balance balance balance

1. Eg Ethoxylated Alcohols as sold by the Shell Oil Co.

2. Ethoxylated tetraethylenepentamine (PEI 189 E15-Elg) according to U. S. 4,597,898 Vander Meer issued July 1,1986.

3. Bleach stable variant of BPN' (Protease A-BSV) as disclosed in EP 130,756 A January 9,1985.

4. Subtilisin 309 Loop Region 6 variant.

5. Proteolytic enzyme as sold by Novo.

6. Soil release polymer according to U. S. Patent 4,702,857, Gosselink, issued October 27, 1987.

7. Balance to 100% can, for example, include minors like optical brightener, perfume, suds suppresser, soil dispersant, chelating agents, dye transfer inhibiting agents, additional water, and solvents, etc.

As described herein above, to measure the effectiveness of the surfactant pastes of the present invention as suitable for use in non-yellowing and non-color forming compositions, the compositions formulated using the surfactant paste produced by the process of the present invention are evaluated on a Coleman Spectrophotometer model 295.

The Coleman meter measures the % transmittance (0-100) of a chosen frequency of visible light through the product held in a standard glass sample vial. The wavelength of the light used to measure the suitability of the formulations using the surfactant pastes of the present invention is 470 nm., which effectively measures the yellowing of compositions. The meter is calibrated to measure 100% transmittance through the standard vial when it contains distilled water. The sample vial is then filled with the product to be evaluated and the sample's % transmittance read. Higher % transmittances are therefore preferred when the objective is to achieve colorless products according to the present invention. The liquid, non-color-added products of the present invention have transmittances of at least about 60%, preferably at least about 90%, more preferably at least about 95%.

EXAMPLE 13 An example which demonstrates the process of the present invention is described herein below.

Acidic surfactant mixture having a specific gravity of approximately 1 and a viscosity of 200 cps at 37 °C is admixed at a rate of 446 mL/min of surfactant mixture with a source of hydrogen peroxide comprising 5 % hydrogen peroxide, 5% water, and 90% ethanol delivered at a rate of 30 mL/min, into a static in line mixer. The admixture is then pumped into a cooling coil where the admixture has a residence time of approximately 1 min. The admixture is then pumped into a vessel and neutralized by the addition of sodium hydroxide and other co-surfactants until the final pH is approximately 8. The resulting surfactant paste is used without further purification in light duty liquid cleaning compositions.

For acid mixes wherein the flow rate of the acid paste introduced into step (a) of the reaction is relatively slow, then longer contact times with a lower level of peroxide is desirable. However, under these circumstances the formulator may vary either: i) the peroxide concentration; ii) the amount of pre-mix which is used in those cases where a pre-mix is desirable; or iii) the contact time between peroxide and acid paste.