Background and prior art Detergent compositions for fabric or hard surface cleaning typically comprise a surfactant system whose role is to assist in removal of soil. Such detergent compositions predominantly comprise non-soap surfactants. Various abrasives, fillers, builders, and other ingredients such as colour, perfume, preservatives, etc. may also be incorporated suitably.

Cleaning compositions in the solid form are much cheaper than liquids because of low cost packaging and these are very popular forms in developing countries. Amongst the solid form, bars are gaining popularity and growing rapidly in the market of developing countries because of better value delivery.

Variegated, striped, marbled or mottled soap bars have been known for many years and allow for more than one colour in the bar in specific or mosaic pattern. Initially, as laundry soaps, they contained colouring materials, such as bluing agents, which functioned as aids for the whitening of clothing. In recent years, however, interest in such bars has been primarily due to the possibility of producing attractive designs therein, which would be preferred by consumers. Multicoloured soap bars are now mainly used for skin cleansing purpose. Thus, a marble pattern on soap gives it a rich appearance and stripes or other similar configurations make the soap distinctive.

The manufacture of non-soapy striped detergent bars is more difficult than the production of striped soap bars by the methods used for striping soap bars. This is because the synthetic surfactants such as sodium linear alkyl benzene sulphonate used as active ingredients in detergent bars are more soluble, and hence the striping dyes tend to diffuse out in the body of the detergent bars very quickly. It is important to maintain the differently coloured stripes separate and distinct in appearance, while ensuring that they are satisfactorily fused together so that they do not prematurely come apart in use and do not crack, become rough or pebbly at interfaces or dissolve at different rates. Therefore, as a part of the technology, one has to strike a fine balance between the conflicting requirements of (a) striping coloured material fusing with the detergent bar and becoming an integral part of the bar, and (b) striped coloured materials not to diffuse into the body of the bar to give a homogeneous colour to it.

Striped soap bars are generally manufactured by (i) using different coloured soap or scarp soap (ii) extrusion of different strands of coloured soap through a die to get multi- coloured bars (US-A-4,196, 163, Henkel) or (iii) injection of a fluid during the process of extrusion (US-A-3,890, 419, Armour- Dial, Inc.).

The present invention does not employ any sophisticated dies design as in point (ii) above. Injection of fluid during extrusion, as in point (iii) above does not work since such a fluid diffuses very quickly in the base NSD dough. Point (i) relates to the making of soap bars and the same has not been disclosed for NSD bars in literature. If scrap NSD bars were to

be made as in point (i), there would not be any integrity in the bar, as NSD bars have lesser binding force than the soap bar.

NSD bars produced through point (i) would thus disintegrate and would not produce a proper striped bar. Therefore, it is not possible to employ the processes described in prior art for the manufacture of striped non-soap detergent bars used for fabric wash or hard surface cleaning. It is specifically advantageous to develop a process to manufacture non-soap detergent bars with stripes because such bars will give a visual cue and it gives a rich appearance, and stripes also make the detergent bar distinctive.

It is the object of the present invention to formulate striped detergent bars and provide processes to manufacture the same.

It has been possible to introduce soap noodles having a definite rheology directly to the extruder during plodding of the non-soap detergent bars whereby the soap forms a stripe that is distinct from the main formulation. It will thus be possible to load the required actives and benefit agents in the soap and keep it spatially separated from the bar formulation.

Definition of the invention Thus, according to the present invention there is provided a striped predominantly non-soap detergent bar composition comprising 5 to 50% by weight detergent active wherein the soap level is not greater than 25 % of the total detergent active, 0.1 to 10 % by weight of the said bar being a striping formulation comprising soap, non-soap or a mixture thereof. The said striping formulation comprises either 0 to 80% wt soap or 0 to 50% wt synthetic non-soap detergent or combinations thereof, with 5 to 30% wt water and 0 to 70% wt inorganic fillers.

According to a preferred aspect of the present invention there is provided a striped predominantly non-soap detergent bar composition comprising 10 to 30 % by weight detergent active wherein the soap level is not greater than 10 % of the total detergent active, 1 to 5 % by weight of the bar being a striping formulation comprising soap, non-soap or a mixture thereof.

According to yet another preferred aspect of the present invention, striping is achieved by using a dough comprising 50 to 80% by weight of soap, 10 to 40% by weight of water and 0 to 20% by weight of inorganic fillers.

The formulation may be prepared using preformed detergent actives or can be prepared by generating the actives by reacting the precursor of the detergent active with an alkali.

According to another aspect of the invention there is provided a process for preparing a striped predominantly non-soap detergent bar composition comprising 5 to 50 % by weight detergent active wherein the soap level is not greater than 25 % by weight of the total active detergent, 1 to 5 % by weight of the bar being a striping formulation comprising soap, non- soap or a mixture thereof, which process comprises the steps of: i. reacting a precursor of the detergent active with an alkali. ii. optionally adding detergent actives, builders, fillers and minor ingredients and converting the product into bars by plodding while introducing 0.1 to 10 % weight of a marbling formulation in the form of noodles based on the weight of the main formulation, at rate of which is a

fraction of the feed rate of the main formulation given by the formula : Fsoap/Fbar fonulation = x/ (100-x) n where Fsoap stands for the feed rate of marbling formulation in the form of noodles which is the striping material, Fformulation stands for the feed rate of main formulation, and x stands for the weight % of the stripes in the final formulation. iii. extruding the bar formulation along with the noodles of the striping formulation.

The striping formulation is prepared separately by mixing soap, non-soap or a mixture optionally with upto 70% by weight inorganic particulates and converting the same into noodles.

Detailed description of the Invention: The essential feature of the invention is a striping detergent bar composition that comprises predominantly non-soap detergent actives and is striped with a striping formulation comprising soap or non-soap or a mixture.

The detergent active: The detergent active used in the bar is predominantly non-soap although some amount of soap can also be incorporated. The actives are selected from soap or non-soap actives that may be anionic, nonionic, cationic, zwitterionic or amphoteric in nature and it is particularly preferred that the soap level does not exceed 25% by weight of the composition. However, it is preferably anionic and specific detergent actives used in detergent bar technology are described in literature, for example in Surface Active Agents and Detergents, Volume II by Schwartz, Perry and Berch (Interscience Publishers, N. Y. 1958).

Specific examples of suitable anionic actives useful in this invention is soap or non soap selected from linear and branched alkyl benzene sulphonates, alkane sulphonates, secondary alcohol sulphates, primary alcohol sulphates, alpha olefin sulphonates, alkyl ether sulphates, fatty acyl ester sulphonates, alkyl carboxylates and mixtures of these.

When the detergent active is soap, the term total fatty matter, usually abbreviated to TFM is used to denote the percentage by weight of fatty acid and triglyceride residues present in soaps without taking into account the accompanying cations.

For a soap having 18 carbon atoms, an accompanying sodium cation will generally amount to about 8% by weight. Other cations may be employed as desired for example zinc, potassium, magnesium, alkyl ammonium and aluminium.

The term soap denotes salts of carboxylic fatty acids. The soap may be derived from any of the triglycerides conventionally used in soap manufacture-consequently the carboxylate anions in the soap may contain from 8 to 22 carbon atoms.

The other detergent active compounds may be anionic, nonionic, cationic, zwitterionic or amphoteric surfactants, or mixtures thereof as are well known to those skilled in the art can also be incorporated in the formulation. Especially preferred are compositions in which the anionic detergent active comprises of alkyl benzene sulphonate (LAS).

The striping formulation: The composition used for striping the bar may be entirely soap or non-soap and it is also possible to use a mixture of both soap and non-soap actives. It is preferred that the striping is to an extent of 0. 1 to 10% by weight of the bar and more

preferably 1 to 5% by weight of the bar. It is preferred that the striping formulation is achieved by using a dough comprising of 50 to 80% soap, 10 to 40% water and 0 to 20% inorganic fillers. In a typical example, the marbling formulation could be: 77% soap, 1% salt or inorganic fillers and 22% water.

Builders: The detergency builders used in the formulation are preferably inorganic and suitable builders include, for example, alkali metal aluminosilicates (zeolites), alkali metal carbonate, sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), citrates, sodium nitrilotriacetate (NTA) and combinations of these. Builders are suitably used in an amount ranging from 0 to 30%.

Inorganic particulates : Inorganic particulate phase is not an essential ingredient of the formulation but may be incorporated especially for hard surface cleaning compositions. Preferably, the particulate phase comprises a particulate structurant and/or abrasive, which is insoluble in water. Suitable inorganic particulates can be selected from, particulate zeolites, calcites, dolomites, feldspars, silicas, silicates, other carbonates, bicarbonates, borates, sulphates and polymeric materials such as polyethylene.

The most preferred inorganic particulates are calcium carbonate (as Calcite), mixtures of calcium and magnesium carbonates (as dolomite), sodium hydrogen carbonate, borax, sodium/potassium sulphate, zeolite, feldspars, talc, koalin and silica.

Calcite, talc, kaolin, feldspar and dolomite and mixtures thereof are particularly preferred due to their low cost and colour.

Other conventional inorganic particulate structurants such as alumino silicate, boro-silicate structuring, boro-alumino silicate or calcium alumino silicate may be generated in situ or readily available forms can be incorporated.

Other additives: Other additives such as one or more water insoluble particulate materials such as polysaccharides such as starch or modified starches and celluloses may be incorporated.

Minor additives: Minor and conventional ingredients preferably selected from enzymes, antiredeposition agents, fluorescers, colour, preservatives and perfumes, also bleaches, bleach precursors, bleach stabilisers, sequestrants, soil release agents (usually polymers) and other polymers may optionally be incorporated up to 10 wt%.

The detergent formulation and the marbling formulation in the form of noodles are mixed during extrusion. The ratio of the torque of the striping formulation to the torque of the base formulation is maintained in the range 0.3 to 1.5.

Illustrations of a few non-limiting examples are provided herein showing comparative results of the composition prepared by the present invention.

Examples: i. Effect of Torque on Striping: Detergent bars (Comparative Example A and Example 1) having a composition described in Table 1 was prepared by mixing the ingredients in the proportion mentioned and extruding the bar in a conventional manner. In Comparative Example A no striping formulation was introduced where as Example 1 the striping formulation described in Table 1 was converted into noodles and introduced during extrusion. The ratio of the non-soap detergent formulation to the striping formulation was 95: 5.

Different torques were maintained by varying the moisture content of the marbling formulation. The torque was measured using a Rheocord-90 Haake.

Table 1 Non Soap Detergent Bar Composition Formulation : % weight. Example A Example 1 Sodium linear alkyl benzene 20. 0 20. 0 sulphonate Builder 18 18 Aluminium sulphate 2. 5 2. 5 Alkaline silicate 1. 5 1. 5 Inorganic particulates 48. 4 43. 4 Minor ingredients 2. 5 2. 5 Water To 100 To 100 Striping formulation : 0 5 Soap-77% of striping formulation Salts (specify)-1% of striping formulation Moisture-22% of striping formulation The data on the moisture level of the striping formulation (in Example 1) and the corresponding torque are presented in Table 2. Desired torque can be obtained by adjusting the moisture

level of the base. Table 2 gives a typical example of such adjustment and the torque obtained for the different moisture level.

Table 2 % moisture in the coloured Corresponding torque (Nm) striped soap 29. 8 2 Nm 22 5 Nm 18 10 Nm 13 25 Nm It was seen that striping can be obtained if the torque of the striping base is in the range of 2 to 25 Nm, and the best striping is obtained if the torque in the range of 5 Nm-10 Nm. Less than 2 Nm (obtained with striping material having higher moisture content) will give uniform smearing of the striping material on the surface of the bar, whereas greater than 25 Nm (obtained by drying off some moisture off the striping material) will give clumps of non-uniform colour intensity. ii. Effect of Concentration of the striping material: Different weight % of soap stripes based on overall formulation was studied keeping the torque of striping soap base as 5 Nm.

The composition of the bar was as described in Table 1 (for Example 1).

Table 3 % of soap Marbling < 0.2 Hardly visible 0.2 % Good 0.5 % Good 1 % Good 2 % Good 4 % Good >4% More Spread Out

It was possible to stripe the detergent bar with the marbling formulation at a concentration 0.2 to 4% to obtain detergent bars with good aesthetic effect. iii. Delivery of Benefit Agents: Detergent bars having a composition described in Table 1 were prepared. In Comparative Example B the 2% soap and 1% fluorescer was incorporated into the composition thoroughly mixed and in Example 2,2% soap with 1% fluorescer was used to stripe the detergent bars. These bars were tested for fluorescer delivery on fabrics. Soiled fabric was washed using the bars of Comparative Example B and Example 2 and the fluorescer delivery benefit was measured by taking the difference in the reflectance of soiled and cleaned fabric at 460nm (R460), with contribution from ultra-violet radiation incorporated. The measurements were carried out on a Macbeth Colour-eye 7000A reflectometer.

The protocol used for detergency was as follows. The bars of Examples B and 2 were fixed in the rate of wear (ROW) jig apparatus. WFK 10D cloth was cut into 10x30 cm swatches. The swatches were fixed on the trays and rubbed in a to and fro manner with the respective bar for 10 seconds in the ROW jig

and then brushed for 10 sec. The fabrics were then rinsed three times with water, dried and the reflectance then measured.

The data is presented in Table 4. The data shows that the striped bars showed enhanced fluorescer delivery as compared to the one where the ingredients were blended in the formulation.

Table 4 Detergent bar AR (460) on WFK 10D Striped bar (Example 2) 20 Plain bar (Example B) 14

The data show that the detergency benefit with fluorescer effect is significantly superior for striped bar (Example 2) as compared to the plain unstriped bar (Example B). This shows that benefit agents can be incorporated in the striping to obtain enhanced benefit delivery.