MXPA04008235A - Detergent composition and process for manufacture.. - Google Patents

Abstract

Described is a process for preparing zinc oxide with a particle size lower than 1 micron, which comprises the following steps: a. generating zinc molecular species in an alkaline phase; b. neutralizing said alkaline phase with an acid in the presence of surface active agents or surface active agent precursors, and c. generating nanoparticles by polymerizing molecular zinc by means of reducing pH.

Description

COMPOSITION OF IMPROVED DETERGENT AND PROCESS FOR MANUFACTURE The invention relates to a particulate sub-micron zinc oxide (ZnO) active / benefit agent delivery system and its manufacturing process. The ZnO nanoparticle delivery system has multiple purposes and can be used for deodorants, sunscreens, masking skin tone, sebum control benefits, etc. The invention also relates to soap / detergent compositions for personal cleansers / fabric washing / hard surfaces and cosmetic products to be worn, which incorporate such an active agent / zinc oxide benefit delivery system of nanoparticles, since an improved process for preparing soap / detergent compositions comprising generating such an active / benefit agent delivery system of submicron particles of zinc oxide in the presence of surface active agents. Cleaning compositions containing specific active ingredients that provide repair, maintenance and skin improvement benefits are formulated in various forms, such as bars, liquids, gels, pastes, etc. These compositions aim to deliver the benefit during the use of the products while the cleaning is performed. The cosmetic formulations further, such as, for example, antiperspirant / deodorant, containing fragrance or other cosmetic formulations, are applied topically to human skin in a variety of physical forms, including aerosol sprays, solid sticks, extrudable solids, creams and liquids to deliver similar skin benefits. Several active ingredients generally incorporated in these formulations are sunscreens, such as organic sunblocks, physical sunblocks, humectants, odor suppressants, skin lightening agents, emollients, exfoliating agents, etc., to deliver specific benefits to the skin. US4094807 (Lever Brothers, 1978) discloses a method for preparing detergent sticks containing from about 0.1% to about 2% by weight of zinc oxide useful for delivering benefit agents, wherein the zinc oxide is formed into a paste containing from about 10% to about 80% by weight of said oxide with a liquid medium, the paste is added to and mixed with a detergent material in the mixing step, and the detergent material is milled, extruded and stamped to form the bars . This describes a specific method for incorporating zinc oxide into a detergent bar in the form of a paste in the mixing step, as otherwise detergent bars containing free fatty acids show a gritty feel during use. Preferably, the zinc oxide used has a particle size distribution so that no more than about 5% by weight of the oxide is retained in a sieve of 10 microns and no more than about 3% by weight is retained in a sieve of 30 microns. Perspiration or sweating is basically a clear fluid excreted by the sweat glands. Sweat in combination with skin bacteria provides an adequate means for the production and production of biological proteases or proteolytic enzymes that contribute to the perspiration / perspiration odor. Control of such body odors is often achieved through the use of deodorant or antiperspirant products, particularly in the underarm area of the body in addition to cleaning. Zinc oxide is well known as an ingredient used quite extensively for the prevention of bad odor in deodorant products for a long time. US5403506 (Church &Dwight, 1995) discloses detergent deodorizing compositions comprising a surfactant, for example, a synthetic detergent or soap, and as a deodorizing component, about 0.1 to 5.0% by weight of zinc oxide having an average particle size not greater than about 10 microns and a surface area of at least about 90 m2 / g. In order to avoid the gritty feeling, you have to choose very low particle size material. There are also several references, which show that in order to provide aesthetically acceptable sunscreen compositions, which are transparent when applied, the zinc oxide used must be nanomized. US20030017122 (Jacob, 200) describes the benefits of using micronized zinc oxide in cosmetic formulations and its superiority over commercially available zinc oxide, which have a much larger particle size.

Zinc oxide is usually obtained as a coarse powder form, which is micronized in the dry state as is conventional, or can be micronized in an oil, preferably a vegetable oil, which helps to break down zinc oxide in ultrafine particles and, at the same time, coat the particles with the oil, which promotes maximum absorbance stability, and has to prevent the agglomeration and coalescence of zinc oxide. The powder of zinc oxide is usually converted into the desired state of particulate size by conventional methods, for example, by grinding the powder in the form of coarse particle, in the presence of auxiliary Suitable milling and using grinding apparatus known, for example, a jet, ball, vibration or hammer mill, preferably a high-speed stirring mill or impact mill, especially a rotating ball mill, vibration mill, tube mill or bar mill. These processes are complex and also add cost. The acquisition of submicron particles of ZnO materials is found, in this way, of extensive work and generally very expensive. It is also found that in addition to using ZnO material of very small particle size to produce bars of soap aesthetically good and free of sand, it has to add specific processing, such as good dispersion and presence of free fatty acids, which again adds process complexities and product cost. In this way, the basic objective of the present invention is to provide a system of asset delivery / benefit agent of particulates of ZnO sub-microns obtained from molecular zinc species, which would be economical and simple to obtain, and would also provide wide range benefit applications, such as in aesthetically good and sand-free soap / detergent bars, deodorants, sun blockers, masked skin tone, sebum control benefit, etc. Another objective is directed to providing cleaning and / or cosmetic compositions and the like with improved benefit agent product and / or delivery features, during use involving a selective submicron zinc oxide delivery system. Yet another object of the present invention is directed to provide an improved method of manufacturing cleansing / cosmetic formulations, including a detergent composition that involves the in-situ generation of a submicron ZnO formulation to obtain detergent bars with Improved hardness, sensation in addition to properties / characteristics of desired benefit agent. Thus, in accordance with the present invention there is provided a particulate zinc oxide benefit / benefit agent delivery system comprising ZnO particulates of size smaller than 1 miera, wherein said ZnO particulates are obtained from molecular species of ZnO. zinc. According to a preferred aspect, the particulate zinc oxide active / benefit agent delivery system of the invention comprises ZnO particulates of size smaller than 1 miera, wherein said ZnO particulates are formed from molecular species of zinc. in the presence of active surface agents. According to another aspect of the present invention, there is provided a process for the manufacture of the particulate zinc oxide particulate active / benefit agent delivery system of particle size less than 1 miera, comprising: generating the molecular species of zinc in an alkaline phase; neutralizing the alkaline phase of molecular zinc with an acid in the presence of surface active agents; and generate nanoparticles by polymerization of molecular zinc by reduction in pH. It has been found by means of the present invention as described above, that the active / effective benefit delivery system of zinc oxide sub-micron particles with a particle size less than 1 miera, can be generated in the presence of active surface agents. The molecular species of zinc can be generated, preferably, by dissolving zinc metal or zinc oxide in an alkaline solution. The alkaline zinc solution is then neutralized with an acid in the presence of surface active to generate nanoparticles by molecular zinc polymerization by reduction in pH. If the acid is an acid precursor of surface active anionic agent, in that case there is no need to add surface active agent separately. In the case of an active portion that is different from the surface active agent precursor, a nonionic / anionic surfactant needs to be present.

The generation of ZnO through a molecular zinc species according to the invention as discussed, is economical and simple, compared to the other known processes used for the manufacture of submicron-sized zinc oxide particles. The delivery system of the invention is useful in formulations such as sunscreens including organic sunblocks, physical sunblocks, humectants, odor suppressants, skin lightening agents, emollients, exfoliating agents, etc., to deliver the benefits of specific skin In accordance with another aspect of the present invention, there is provided a cleansing / cosmetic composition comprising an active / benefit agent delivery system having said ZnO particulates of size less than 1 miera, wherein said ZnO particulates are formed of molecular species of zinc. According to a preferred aspect, the cleaning / cosmetic composition comprising an asset / benefit agent delivery system comprising ZnO particulates of size less than 1 miera, wherein the ZnO particulates are formed from molecular species of zinc in the presence of active surface agents. Thus, it is possible by the present invention to formulate compositions comprising zinc oxide sub-micron sized particles having a particle size of less than 1 mire and such compositions will give a significantly higher delivery of the benefit agents.

According to another aspect of the present invention, there is provided an improved process for the preparation of a cleansing / cosmetic composition comprising providing: the benefit / benefit agent delivery system comprising particulate ZnO obtained from molecular Zn species of less of 1 miera of size in the presence of active surface agents; and - obtaining the cleaning / cosmetic composition including sub-micron ZnO following the conventional procedure. According to a preferred aspect, the manufacturing process of the detergent composition comprises: - in situ generation of the particulate ZnO active / benefit agent delivery system of less than 1 miera of size from a molecular species of zinc in the presence of active surface agents; - obtaining the detergent composition including the submicron ZnO of said molecular Zn species, following the conventional procedure. The invention thus directed to an effective agent / benefit delivery system of zinc oxide sub-micron particles with a particle size less than 1 miera, generated from molecular species of zinc in the presence of active agents Of surface. The generation of ZnO through molecular zinc species according to the invention as discussed, is economical and simple as compared to other known processes used for the manufacture of zinc oxide particles of submicron size. The system of Delivery of the invention is useful in the manufacture of formulations, such as solar biociders, including organic sun blockers, physical blockers, humectants, odor suppressants, skin lightening agents, emollients, exfoliating agents, etc., to deliver specific benefits To the skin. Accordingly, this invention further provides an improved process for preparing a detergent composition comprising - from 5% to 80% by weight of detergent active; from 0.1% to 20% by weight of zinc oxide with a particle size of less than 1 mire; - from 0 to 30% by weight of a salt of a carboxylic acid, which has an equivalent weight of less than 150; - from 10% to 90% by weight of water; - optionally other benefit agents; and - 0-30% detergent builder; said process comprises the steps of a. reacting one or more detergent active precursors, optionally in the presence of carboxylic acid, which has an equivalent weight less than 150, as described herein with an aqueous solution of alkali metal cincate with a solids content of 1% to 55%, wherein the ZnO to M20 is in a proportion of 0.002 to 2 by weight, where M is either sodium or potassium, to obtain a sub-micron zinc oxide mixture with a particle size less than 1 miera and active detergent at a temperature between 25 ° C up b. adding, if desired, other detergent actives, formers and minor additives, as described herein to the mixture of step (a); and c. convert the product into the desired shape by the conventional method. In accordance with the preferred aspect of the invention, there is provided an improved process for preparing a detergent composition comprising: from 5% to 80% by weight of detergent active; - from 0.1% to 10% by weight of zinc oxide with a particle size of less than 1 mire; from 1% to 15% by weight of a salt of a carboxylic acid, which has an equivalent weight of less than 150; - from 10% to 90% by weight of water; - optionally other benefit agents; - 0-30% detergent builder; said process comprises the steps of: a. reacting one or more detergent active precursors in the presence of carboxylic acid, which has an equivalent weight of less than 150, as described herein, with an aqueous solution of alkali metal cincate with a solids content of 1% to 55%, wherein the ZnO to M20 is in a proportion of 0.002 to 2 by weight, where M is either sodium or potassium, to obtain a sub-micron zinc oxide mixture with a particle size less than 1 miera, active detergent and carboxylic acid salt at a temperature between 25 ° C to 95 ° C; b. add, if desired, other detergent actives, formers and minor additives, as described herein to the step mixture (a) c. convert the product into the desired shape by the conventional method. It is also possible to isolate the nanoparticles generated by the above process from the surfactant matrix and can be used to form other creams and lotions. Thus, the invention also relates essentially to a process for the preparation of soap / detergent compositions comprising sub-micron particles generated in situ from zinc oxide (ZnO) in the presence of surface active agents. The ZnO nanoparticles generated are of multiple purposes and can be used for deodorants, sunscreens, masking skin tone, sebum control benefits, etc. The carboxylic acid mentioned in step (a) may be those having an equivalent weight of less than 150, may be selected from aliphatic monocarboxylic acids other than fatty acids and their polymers, and more preferably, are carboxylic acids of C | to C5 and its polymers. Other suitable carboxylic acids are di-, tri- or polycarboxylic aliphatic or aromatic acids and hydroxy- and amino carboxylic acids. The carboxylic acids can be selected from monocarboxylic acids, such as acetic acid, propionic acid, acid butanoic, isobutyric acid, etc., di / polycarboxylic acids, such as, succinic, malonic, maleic, maleic, citric and tartaric acids, etc. or its polymers, such as polyacrylic acids, acrylic-maleic copolymers, etc. Selected hydroxy carboxylic acids of glycolic, lactic, ricinoleic or amino carboxylic acids selected from glycine, valine, leucine, may also be employed. The alkali metal cincate solution which can be used for neutralization was generated by the reaction of zinc oxide with aqueous solution of sodium or potassium hydroxide at an elevated temperature. A solubility stabilizer selected from any soluble inorganic or organic salt, polymer, other alkaline materials, alkali metal salt of citric acid, tartaric, gluconic, polyvinyl alcohol, etc., may be additionally incorporated during the preparation of metal zinkate solution. alkaline. The active detergent used in the process can be non-soap or soap surfactants. The term total fat matter, usually abbreviated TFM, is used to denote the weight percentage of fatty acid and triglyceride residues present in soaps without considering 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 aluminum. The term soap denotes salts of carboxylic fatty acids. He soap can be derived from any triglyceride conventionally used in the manufacture of soap - consequently the carboxylate anions in the soap can contain from 8 to 22 carbon atoms. The soap can be obtained by saponifying a fat and / or a fatty acid. Fats or oils generally used in the manufacture of soap may be such as tallow, tallow tallow, palm oil, palm stearin, soybean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil and others. In the above processes, the fatty acids are derived from oils / fats selected from coconut, rice bran, walnut, tallow, palm, palm kernel, cottonseed, soybean, castor, etc. The fatty acid soaps can also be prepared synthetically (for example, by the oxidation of petroleum or by the hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids, such as those present in tallow oil, can be used. Naphthenic acids are also suitable. The tallow fatty acids can be derived from several animal sources and generally comprise about 1-8% myristic acid, about 21-32% palmitic acid, about 14-31% stearic acid, about 0-4% palmitoleic acid , approximately 36-50% oleic acid and approximately 0-5% linoleic acid. A normal distribution is 2.5% myristic acid, 29% of palmitic acid, 23% stearic acid, 2% palmitoleic acid, 41.5% oleic acid and 3% linoleic acid. Other similar mixtures, such as those of palm oil and those derived from various tallow and animal larva, are also included. Coconut oil refers to mixtures of fatty acids having an approximate carbon chain length distribution of 8% C8l 7% C10, 48% C12, 17% C14, 8% C16, 2% C18 , 7% oleic acid and 2% linieic (the first six fatty acids listed being saturated). Other sources having similar carbon chain length distributions, such as palm kernel oil and babassu oil, are included within the term coconut oil. A normal fatty acid mixture consisted of 5% to 30% coconut fatty acids and 70% to 95% fatty acids of ex-hardened rice bran oil. Fatty acids derived from other suitable oils / fats, such as walnut, soy, tallow, palm, palm kernel, etc., may also be used in other desired proportions. The composition according to the invention, preferably will comprise detergent actives which are generally chosen from both anionic and nonionic detergent actives. Suitable anionic detergent active compounds are water soluble salts of organic sulfuric reaction products, having in the molecular structure an alkyl radical containing from 8 to 22 carbon atoms, and a radical selected from sulfuric acid ester or acid radicals sulfonic acid and mixtures thereof. Examples of suitable anionic detergents are sulfates of Sodium and potassium alcohol, especially those obtained by sulfating the higher alcohols produced by reducing tallow glycerides or coconut oil; Sodium and potassium alkyl benzene sulphonates, such as those in which the alkyl group contains from 9 to 15 carbon atoms; sodium alkyl glyceryl ether sulfates, especially those ethers of higher alcohols derived from tallow and coconut oil; fatty acid monoglyceride sulphates of coconut oil; sodium and potassium salts of sulfuric acid esters of the reaction product of one mole of a higher fatty alcohol and from 1 to 6 moles of ethylene oxide; sodium and potassium salts of alkyl phenol ethylene oxide sulfate with 1 to 8 ethylene oxide molecule units and in which the alkyl radicals contain from 4 to 14 carbon atoms; the reaction product of fatty acids esterified with isethionic acid and neutralized with sodium hydroxide where, for example, the fatty acids are derived from coconut oil and mixtures thereof. Preferred synthetic, water-soluble anionic detergent active compounds are the alkali metal salts (such as sodium and potassium and alkaline earth metal, eg, calcium and magnesium), higher alkyl benzene sulphonates and mixtures with sulfonates olefin and higher alkyl sulfates, and monoglyceride sulfates of higher fatty acids Suitable nonionic detergent active compounds can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic nature, with an organic hydrophobic compound, which may be aliphatic in nature or aromatic alkyl. The length of the hydrophobic or polyoxyalkylene radical, which is condensed with any particular hydrophobic group, can be easily adjusted to produce a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Particular examples include the condensation product of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as a condensate of coconut oil, ethylene oxide having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols, the alkyl group of which contains from 6 to 12 carbon atoms with 5 to 25 moles of ethylene oxide per mole of alkylphenol; condensates of the reaction product of ethylene diamine and propylene oxide with ethylene oxide, the condensate containing from 40% to 80% of polyoxyethylene radicals by weight and having a molecular weight from 5,000 to 11,000; tertiary amine oxides of structure R3NO, wherein one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl group, for example, dimethyldodecylamine oxide; tertiary phosphine oxides of structure R3PO, wherein one group R is an alkyl group of 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for example, dimethyldodecylphosphine oxide; and dialkyl sulfoxides of structure R2SO, wherein the group R is an alkyl group of 10 to 18 carbon atoms and the another is methyl or ethyl, for example, methyltetradecyl sulfoxide, fatty acid alkylolamides; alkyl oxide condensates of fatty acid alkylolamides and alkyl mercaptans. It is also possible to include amphoteric or zwitterionic detergent actives in the compositions according to the invention. Suitable amphoteric detergent active compounds which optionally may be employed are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic group solubilizing in water, for example 3- Sodium dodecylamino-propionate, sodium 3-dodecylaminopropane sulfonate and sodium? -2-hydroxydecyl-N-methyltaurate. Suitable zwitterionic active detergent compounds which optionally can be used are derivatives of aliphatic quaternary ammonium, sulfonium and phosphonium compounds, having an aliphatic radical of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic group solubilizing in water, for example, propane-1-sulfonate betaine of 3- (NN-dimethyl-N-hexadecylammonium) protpane-1-sulfonate betaine of 3- (dodecylmethyl sulfonium) and ethane sulfonate of 3- (cetylmethylphosphonium) betaine. Suitable builders for use in the formulation are preferably inorganic and suitable formers include, for example, alkali metal aluminosilicates (zeolites), alkali metal carbonate, sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), citrates, sodium nitrilotriacetate (NTA) and combinations of these. The formers are suitably used in an amount ranging from 1 to 30% by weight. Examples of suitable benefit agents include humectants and humectants include polyols, glycerol, cetyl alcohol, carbopol 934, ethoxylated castor oil, paraffin oils, lanolin and its derivatives. Silicone compounds, such as silicone surfactants such as DC3225C (Dow Corning) and / or silicone emollients, silicone oil (DC-200 Ej-Dow Corning), may also be included. Sunscreens such as 4-butyl tertiary-4'-methoxy dibenzoylmethane (available under the tradename PARSOL 1789 from Givaudan) and / or 2-ethyl hexyl methoxycinnamate (available under the tradename PARSOL MCX from Givaudan) or others solar blockers UV-A and UV-B. Water soluble glycols, such as, propylene glycol, ethylene glycol, glycerol, can be employed at levels of up to 10%. Other inorganic particulates can be optionally incorporated into the formation and is especially useful for hard surface cleaning compositions. Preferably, the particulate phase comprises a particulate and / or abrasive structurant, which is insoluble in water. In the alternative, the abrasive can be soluble and present in such excess to any water present in the composition, that the solubility of the abrasive in the aqueous phase is exceeded and consequently the solid abrasive exists in the composition. Suitable inorganic particulates can be selected from, particulate zeolites, calcites, dolomites, feldspars, silicas, silicates, other carbonates, bicarbonates, borates, sulfates and polymeric materials, such as polyethylene. The most preferred inorganic particulates are calcium carbonate (such as calcite), mixtures of calcium and magnesium carbonates (such as dolomite), sodium acid carbonate, borax, sodium / potassium sulfate, zeolite, feldspars, talc, kaolin and silica. Calcite, talc, kaolin, feldspar and dolomite and mixtures thereof are particularly preferred because of their low cost and color. Inorganic particulate structurants, such as aluminum silicate, can be generated in situ using aluminum sulfate and sodium silicate in the formulation. It is also possible to incorporate sodium alumino-silicate readily available in the formulation. Other additives, such as one or more water insoluble particulate materials, such as talc, kaolin, polysaccharides, such as starch or modified starches and celluloses, may be incorporated. In step (b) of the process, minor and conventional ingredients preferably selected from enzymes, anti-redeposition agents, fluorescers, color, preservatives and perfumes, also bleach, bleach precursors, bleach stabilizers, sequestrants, soil release agents ( usually polymers) and other polymers, optionally up to 10% by weight can be incorporated. The invention is made in any mixer conventionally used in the manufacture of soap / detergent, and preferably is a high-cut kneading mixer. Preferred mixers include plowshare mixer, mixers with kneading members of Sigma type, overlapping multi cleanser, single curved or double arm. The double-arm kneading mixers can be of overlap or tangential design. Alternatively, the invention may be carried out in a helical screw stirrer or multi-head dosing pump / high cut mixer and spray dryer combinations as in conventional processing.

EXAMPLES The invention is described in greater detail below in relation to non-limiting exemplary illustrations.

EXAMPLE 1A Process to obtain the asset / benefit agent delivery system by generating sub-micron size ZnO particles from molecular Zn species. Preparation of sodium cincate. The solution to be prepared had a solids content of 25% (at 500 ° C) and the proportion of ZnO / Na20 = 0.25. Caustic soda flakes (25.8 g) were added to 69.2 ml of water and dissolved with stirring. The caustic solution was heated to 80 ° C. ZnO (5g) was added slowly to the caustic solution and the temperature was raised to 120 ° C. after stirring the solution for 3 h, the solution was cooled to 40 ° C and filtered. The solution was analyzed for the solids content by heating the sample at 500 ° C for 3 h and the Na20 content was determined to titrate the sample with standard HCl solution. The ZnO content was calculated then as (solids content -% Na20).

Obtaining the ZnO particulates from the molecular species of Zn For the purpose, 100 ml of 25% sodium zinkate (obtained as above) was mixed with 5 g of tween 60. It was neutralized with 41.9 g of citric acid as a aqueous solution, to thereby generate nanoparticles by molecular zinc polymerization by reduction in pH. It is possible to isolate the nanoparticles generated by the previous process from the surfactant matrix. For the purpose, the mixture of ZnO and surfactants was dissolved with sufficient quantities of ethanol to dissolve the neutralized detergent actives and ZnO in situ was collected as fine particles, which were centrifuged and viewed under a microscope. Figure 1 shows the image of the ZnO generated in situ in the nano-range. In accordance with the other aspect of the invention, illustrations of a few non-limiting examples showing comparative results of compositions in accordance with the present invention, involving ZnO particulates generated in situ and compositions involving particulates are provided herein. of conventional ZnO.

EXAMPLES 1 & 2 Process according to the invention A batch of 50 kg of soap was prepared by melting a mixture of fatty acids at 80-85 ° C in a steam jacketed mixer and neutralizing with 24% sodium zincarate solution in water. The additional water was added to obtain a moisture content of approximately 33%. The soap mass was spray-dried under vacuum and formed into noodles. The soap noodles were mixed with caustic soda, talc, perfume, color and titanium dioxide in a sigma mixer and passed twice through a triple roller mill. The ground flakes were extruded under vacuum and formed into logs. The logs were cut and stamped on the tablets. (Examples 1 and 2). The sodium zincate solution used for the neutralization was generated by the reaction of zinc oxide (ZnO) with aqueous sodium hydroxide solution (NaOH) at an elevated temperature as discussed under Example 1A above.

EXAMPLES 3 & Process according to the prior art A batch of 50 kg of soap was prepared by melting a mixture of fatty acids at 80-85 ° C in a steam jacketed mixer and neutralizing with 48% sodium hydroxide solution (NaOH) in water The additional water was added to obtain a moisture content of approximately 33%. The soap mass was spray-dried under vacuum and formed into noodles. The soap noodles were mixed with zinc oxide (ZnO) and other ingredients were added and mixed in a sigma mixer, and passed through a triple roller mill twice. The milled flakes were extruded under vacuum and formed into logs. The logs were cut and stamped on the tablets. (Examples 3 and 4). In Example 4, 2% free fatty acids were further added to improve the feeling. The composition details attempted and their results are described in Table 1.

Table 1 Samples prepared as described above were tested for hardness (yield stress) and sensation (grit) by the following procedure. The formation of zinc oxide nanoparticles according to the process of the invention was demonstrated using scanning electron microscopy.

Performance stress The performance stress quantifies the hardness of a bar of soap. The yield stress of the bars at a specified temperature was determined by observation of the degree to which a bar was cut by a heavy cheese wire for a specified time. The apparatus consists of a cheese wire (diameter d in cm) attached to a balanced counter arm, which can pivot freely via a ball race holder. A soap log is positioned under the wire, so that the wire is just in contact with an edge of the log. By applying a weight (W g) directly above the cheese wire, a constant force is exerted on the wire, which will slide in the soap. The area over which the force acts will increase as the depth of cut increases, and therefore, the tension being exerted will decrease until it is exactly balanced by the resistance of the soap and the wire stops moving. The tension at this point is equal to the performance tension of the soap. It was found that the time taken to reach this point was approximately 30 seconds, so that a standard time of 1 min was chosen to ensure that the performance tension had been reached. After this time, the weight was removed and the length of the cut (L in cm) was measured. The tension of Performance is calculated using the semi-empirical formula: Y.S = 3 W X 98.1 Pascal (Pa.) 8 L x d Sensation A standard washing procedure in cold water is followed for estimation of grit by sensation by a group of trained panelists. The rating is given on a scale of 1-10, where the rating of 1 refers to the best feeling and 10 to the poorest. Toilet soaps of acceptable quality generally have a sensation rating below 8.0. It can be seen from Table 1 that ZnO formulations generated in situ (Examples 1 and 2) have superior feel than the post-dosed conZnO formulation (Example 3). It is a common practice in the manufacture of soap, that the sensation of the bars of soap can be dramatically improved by the addition of free fatty acids. Similarly, it was found that the addition of free fatty acids at a level of 2% (Example 4), improved the sensation in the case of post-dosed ZnO, but the formulation developed the grit after one month of storage at conditions ambient. It is known in the literature that the addition of free fatty acids to the post-dosed ZnO formulation can generate grittiness during storage due to the formation of complex formation.

Demonstration of nanoparticle formation The soap bar was fractured by hand and a dimension sample, 1 cm / 1 cm was taken near the upper, lower surface of the bar and the center of the bar. The bar sample was mounted on the top. The sample was coated with crackling (Hitachi E1010 crackling coating) with gold under ~ 7 Pa of vacuum at 50 nm thickness. The coated sample was analyzed in a scanning electron microscope (Hitachi S4700) at room temperature and at a sample chamber vacuum of < < 1 x 10"3 Pa. The electron micrographs of the samples were taken using a secondary electron detector at an acceleration voltage of 20 KV and a filament emission current of 10 μ. Element analysis was performed using an analyzer Horiba EMAX, in image dimension of -400 μ ?? x 300 μ ?? at an acceleration voltage of 20 KV, using a secondary electron detector The elemental composition was calculated by normalizing the percentage by weight of all the detected elements (limit of detection> 0.1% of heavy elements of the matrix.) Element mapping was also performed to observe the distribution of sodium and zinc in these samples Figure 2 shows the soap microstructure showing the absence of any particle inorganic micron size Figure 3 shows the elemental zinc analysis of EDAX from the same photograph, an appearance of bright spots (zinc element) shows a uniform use of ZnO through the product matrix. Additional illustrations of the non-limiting examples of Non-soap detergent formulations are shown herein.

EXAMPLES 5 AND 6 Process according to the prior art A batch of 15 kg of the different formulations described in Table 2 was prepared by using linear alkyl benzene sulfonic acid (LAS acid) as an anionic active precursor, which was taken in a sigma mixer and some amount of water was added. To this mixture of LAS-water, sodium carbonate was slowly added in a stoichiometric ratio and mixed for 10 min for the reaction to be completed. Subsequently, the other particulate structurants such as china clay, feldspar, etc., were added and processed in a conventional manner. To this matrix, aluminum sulfate was added followed by sodium silicate, mixed for 5 min to generate the structurant. (Examples 5 and 6).

EXAMPLES 7 AND 8 Process according to the invention In this case benzene sulphonic linear alkyl acid was neutralized with sodium zincate solution to generate ZnO in situ (Examples 7 and 8). After this, sodium carbonate was added. The remainder of the procedure was followed as for Examples 5 and 6. Formulation details are shown in Table 2.

Table 2 The formulations in Table 2 indicate that the in-use properties of the ZnO in situ formulations (Examples 7 and 8) are similar to the control (Examples 5,6). The ZnO in situ has given an additional hardening to the formulations as seen from the penetrometer data, which was determined by the process described below.

The method of determining the penetration value (PV) followed The penetration value that indicates the hardness of the bar, was measured using a cone penetrometer, the details of a normal instrument and The measurement method are given below.

Cone Type Penetrometer MANUFACTURER: Adair Dutt & Company, Bombay. MEASUREMENT RANGE: 0 - 40 mm VERIFICATION RANGE: 20 in steps of 5 Measurement procedure Leave the complete mass (comprised of a penetrometer needle and standard weight), which just rests on the test sample, drop freely and in this way penetrate the test mass at a specific distance for a specified period of time and read this distance as 1 / 10th of mm. Take the average after repeating the exercise for at least 3 times. A) Yes, it is possible by means of the present invention, to provide a ZnO submicron particulate asset / benefit agent delivery system obtained from molecular zinc species, which would be economical and simple to obtain and would also provide a wide range of beneficial applications, such as in soap bars / detergent aesthetically good and free of grit, deodorants, sun blockers, masking of skin tone, benefit of sebum control, etc. In addition, the invention would provide an improved manufacturing method of cleaning / cosmetic formulations, including a detergent composition involving in situ generation of a synergistic submicron ZnO formulation to obtain detergent bars with hardness. improved, feeling in addition to desired benefit agent delivery features / characteristics.

Claims (9)

1. A process for preparing zinc oxide with a particle size of less than 1 miera, comprising the steps of: a. generate molecular species of zinc in an alkaline phase; b. neutralizing the alkaline phase of molecular zinc with an acid in the presence of surface active agents or precursors of surface active agents; and c. generate nanoparticles by polymerization of molecular zinc by reduction in pH.

2. A process according to claim 1, wherein the molecular species of zinc is generated by dissolving zinc metal or zinc oxide in an alkaline solution.

3. A process according to claim 1 or claim 2, wherein the acid is an acid precursor of a surface active anionic agent.

4. A detergent or cosmetic composition comprising: a. from 0 to 80% by weight of active detergent, preferably 5% to 80% of detergent agent when the cosmetic composition is a detergent composition; b. from 0.1% to 20% by weight of zinc oxide having a particle size of less than 1 mire; c. from 0 to 30% by weight of a carboxylic acid salt, which has an equivalent weight of less than 150; d. from 10% to 90% by weight of water; Y and. from 0 to 30% by weight of a detergent former. The composition according to claim 4, wherein the zinc oxide is made according to the method of any of claims 1 to 3. The composition of claim 4 or claim 5, comprising from 0.1% up to 10% by weight of zinc oxide with a particle size of less than 1 miera. The composition of any of claims 4 to 6, which comprises additional benefit agents. The composition of any of claims 4 to 7, wherein the benefit agent is selected from a sunscreen, humectant, malodor suppressant, skin lightening agent, emollient and an exfoliating agent, or mixtures thereof. . 9. A process for preparing the composition of any of claims 4 to 8, comprising the steps of: i. reacting one or more precursors of a detergent active optionally in the presence of a carboxylic acid, which has an equivalent weight of less than 150 with an aqueous solution of alkali metal cincate with a solids content of 1% to 55%, wherein the zinc oxide to metal oxide (M20) is in a proportion of 0.002 to 2 by weight, wherein M is either sodium or potassium, to obtain a zinc oxide mixture of sub-microns with a size of particle of less than 1 miera and active of detergent at a temperature in the range of 25 ° C to 95 ° C; ii. add other detergent assets, formers and additives smaller than the mixture of step i; or. convert the product into the desired shape by conventional methods.