Soap compositions comprising amorphous aluminosilicate

Abstract

The present invention relates to an extruded soap composition. It more particularly relates to a soap composition which comprises specified type of sodium aluminosilicate and an organic filler to produce soap compositions with high water content that are not only easy to extrude but have the desired hardness.

Description

[0001] SOAP COMPOSITIONS COMPRISING AMORPHOUS ALUMINOSILICATE

[0002] Field of the invention

[0003] The present invention relates to a soap composition. It more particularly relates to a soap composition comprising aluminosilicate that comprises high amount of water and yet exhibits sufficient hardness such that it is easy to extrude and stamp.

[0004] Background of the invention

[0005] Surfactants have been used for personal wash applications for a long time. There are many categories of products in the personal wash market e.g. body wash, face wash, hand wash, soap compositions and shampoos. Products which are marketed as body wash, face wash and shampoos are generally in liquid form and are made of synthetic anionic surfactants. They are generally sold in plastic bottles / containers. Soap compositions and hand wash products generally contain soaps. Soap compositions do not need to be sold in plastic containers and are able to retain their own shape by virtue of being structured in the form of a rigid solid. Soaps bars are usually sold in cartons made of cardboard.

[0006] Soap compositions whether for personal wash purposes or for laundering clothes, are generally prepared through one of two routes. One is called the cast bar route while the other is called the milled and plodded route (also known as extrusion route). The cast bar route has inherently been very amenable in preparing low TFM (total fatty matter) bars. Total fatty matter is a common way of defining the quality of soap. TFM is defined as the total amount of fatty matter, mostly fatty acids, that can be separated from a sample of soap after splitting with a mineral acid, usually hydrochloric acid. In the cast bar soaps, the soap mixture is mixed with polyhydric alcohols and poured in casts and allowed to cool and then the soap compositions are removed from the casts. The cast bar route enables production at relatively lower throughput rates.

[0007] In the milled and plodded route, the soap is prepared with high water content and then spray dried to reduce the moisture content and to cool the soap after which other ingredients are added and then the soap is extruded through a plodder and optionally cut and stamped to prepare the final soap composition. The milled and plodded soaps generally have a high TFM in the range of 60 to 80 weight percent. Milled and plodded soap compositions are also known as extruded soap compositions. They are composed of very many different types of soaps. Most soap compositions comprise both water insoluble as well as water soluble soaps. Their structure is generally characterized by a brick and mortar type structure. Insoluble soaps (called bricks) usually consist of higher chain C16 and C18 soaps (palmitate and stearate soap). They are generally included in soap compositions to provide structuring benefits i.e they provide shape to the bars. Soap compositions also consist of water soluble soaps (which act as the mortar) which are generally unsaturated C18:1 and 18:2 sodium soap (oleate soap) in combination with short chain fatty acids (generally C8 to C12 or even up to C14 soap). Water soluble soaps generally aid in cleaning.

[0008] In addition to about the 60 to 80 wt% TFM, soap compositions presently prepared through the extruded route for personal wash contain about 14 to 22 wt% water. There is a need for developing sustainable technologies where one approach is to develop soaps with lower TFM content and by increasing the water content with no compromise on the cleaning efficacy. The present inventors are aware of various attempts by the present applicants and others to reduce the fatty matter content. These technologies include approaches to structure soap compositions, like inclusion of aluminium phosphate or in situ generation of calcium silicate. Such technologies are not very skin friendly and so are not appropriate for personal washing or for washing fabric by hand. If one simply substitutes the TFM with higher amount of water, it causes problems during extrusion of the soap mass and further the extruded bars are sticky and cannot be stamped easily. The present inventors are also aware of various other approaches including inclusion of natural aluminosilicate clays like bentonite or kaolinite but they are found to not be very efficient in structuring the bars at low amounts.

[0009] The present applicant has also included zeolite in soap compositions to increase the water content e.g. as published in W02020 / 169409. Although this technology enables the production of soap compositions containing 22 to 35 wt% water, the search is on to develop soap compositions that can contain higher amounts of water and yet deliver all the desired consumer benefits. The present inventors with their extensive research experience in the area of aluminosilicate gels, were able to develop even better water holding soap compositions by incorporating in them, specific aluminosilicate where the SiO2 / AI2C>3 mole ratio is less than 5.0. The invention uses zeolite, which are microporous, three- dimensional crystalline solids of aluminium silicate. Aluminosilicate gels have been incorporated in soap compositions but the gels so incorporated were not in the presently claimed SiO2 / AI2C>3 mole ratio and therefore those soaps bars do not exhibit the high-water holding capacity and so are not extrudable in a conventional plodder.

[0010] WO2022180228 (Unilever) relates to an extruded soap bar composition. It more particularly relates to a soap bar composition which comprises specified type of sodium alumino silicate gel to produce soap bars with high water content that are not only easy to extrude but have the desired hardness.

[0011] There are several challenges of processing high moisture soap bar by incorporating beyond 1% moisture in sigma mixer and or soap finishing line especially in presence of starch. Incorporating moisture in sigma mixer leads to lumping, stickiness of the mass, less through put from the plodder.

[0012] However, incorporation of high amount of aluminosilicate in the soap results in a soap mass which is brittle and powdery. Hence converting the mass into noodle and then storing and transportation becomes a challenge.

[0013] Therefore, there is a need to provide for a soap composition comprising high amount of water in the range of 15 to 45 wt% which can be prepared using the extrusion route and is easily and conveniently stampable and wherein the soap composition such as noodles have acceptable characteristics for manufacturing a soap bar with good hardness quality. Through high moisture noodle route adding of moisture in sigma stage can be avoided to meet the moisture target in finish goods. Therefore, high moisture and starch containing formulation can be processed without any processing challenges e.g., lumping, stickiness of the mass, less through put from the plodder.

[0014] Summary of the invention

[0015] First aspect of the present invention relates to a soap composition comprising, a. 18 to 75 wt% of total fatty matter; b. 1.0 to 15.0 wt% of polymeric form of sodium alumino silicate; c. 15 to 45 wt% of water; d. 1 to 45wt% of an organic filler comprising starch; and e. 0.1 to 5 wt% of a pH quencher having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof; wherein the SiCh / AhOs mole ratio of the polymeric form of sodium alumino silicate is equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; and wherein wherein, pH quencher is selected from the group of salts of organic acid, polyacrylic acid and dicarboxylic acid or mixtures thereof.

[0016] In a second aspect, the present invention relates to process comprising the steps of: a. saponifying a fatty matter with an alkali to produce a saponified mass; b. adding sodium aluminate, sodium silicate, and an acid having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof and mixing; and c. adding 1 to 45wt% of organic fillers to step (b) by weight of the resulting soap composition to obtain a mixture; and d. extruding the mixture of step (c) to obtain a soap composition according to the first aspect; wherein water is added at any of the steps (a), (b) or (c).

[0017] Third aspect of the present invention provides use of aluminosilicate and starch in soap bars having moisture in the range of 15 to 45wt% for achieving hardness of at least 3 Kg-F measured at 40°C.

[0018] Detailed description of the invention

[0019] These and other aspects, 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. For the avoidance of doubt, any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight / weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description and claims indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word “about”. Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

[0020] Throughout the specification unless otherwise specified, wt% means weight % of the total weight of soap composition of the present invention.

[0021] Various components of the composition are described in greater detail below.

[0022] Soap Composition

[0023] The present invention relates to a soap composition. By a soap composition it is understood to be a composition which may be used as a soap or a composition which is used to prepare a soap. More preferably the present invention provides a soap composition which is used to prepare soap bars and more preferably extruded soap bars and furthermore preferably soap bars prepared by plough shear mixer. The soap composition of the invention is especially useful for personal cleansing.

[0024] The soap composition of the present invention provides a soap composition comprising, 18 to 75 wt% of total fatty matter; 1.0 to 15.0 wt% of polymeric form of sodium aluminosilicate; 15 to 45 wt% of water; 1 to 45wt% of an organic filler; and 0.1 to 5 wt% of a pH quencher acid having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof; wherein the SiCh / AhCh mole ratio of the polymeric form of sodium aluminosilicate is equal to or less than 3.0; and wherein the sodium aluminosilicate is in amorphous form.

[0025] The present invention is an improvement over WO2022180228 which had some common inventors as it was observed that at high temperatures the amorphous form was not stable and changed to the crystalline form of sodium alumino silicate.

[0026] The composition of the present invention is preferably used or used to prepare a shaped solid for example a bar. The cleaning soap composition is preferably used or used to prepare a wash off product that generally has sufficient amount of surfactants included therein that it is used for cleansing the desired topical surface e.g. the whole body, the hair and scalp or the face. It is applied on the topical surface and left thereon only for a few seconds or minutes and washed off thereafter with copious amounts of water.

[0027] The soap composition may additionally comprise synthetic surfactants selected from one or more from the class of anionic, non-ionic, cationic or zwitterionic surfactants, preferably from anionic surfactants. These synthetic surfactants, as per the present invention, are included in less than 8%, preferably less than 4%, more preferably less than 1% and sometimes absent from the composition. By “absent” it is meant that there is no deliberately added synthetic surfactant in the soap composition of the present invention.

[0028] The soap composition of the invention is capable of stably retaining high amount of water in the range of 15 to 45 wt% by weight of the soap composition as compared to conventional soap composition. Thus, water is preferably at least 15 wt.%, further preferably at least 18 wt.%, still more preferably at least 20 wt.% furthermore preferably at least 23 wt.% but the amount of water in the soap composition is preferably not more than 45 wt.%, still preferably not more than 40 wt.%, most preferably not more than 38 wt.%. In highly preferred aspects, the amount of water in the soap composition ranges from 15 to 45%, more preferably 18 to 40% by weight of the composition.

[0029] To resolve all the challenges of high moisture bar processing, the present inventors have been able to make soap composition by incorporating water structuring technology like sodium aluminosilicate and organic filler such as starch in amounts that do not lead to compromise on the physical and consumer desirable attributes of the soap composition, especially when it is a soap bar which is required to be of requisite hardness.

[0030] Further, it was surprising finding of the present invention that even the form of sodium aluminosilicate used was important for the properties of the resultant soap bar and when the inventors started with the commercially available aluminosilicate- Zeolite 4A which is readily available and known to be used for soaps, but there were problems such as the soap bar with Zeolite 4A could not hold a high moisture content with desired hardness and in some cases when the wt% of Zeolite 4A was altered, efflorescence or cracking was seen. However, when the inventors ventured to experiment with the in situ formation of sodium aluminosilicate, it was completely unexpected finding of the inventors that such soap bars performed much better to contribute towards the hardness property of the soap bar and the sodium alumino silicate generated in situ was more weight efficient than when the Zeolite 4A was used and no efflorescence was seen. After XRD analysis to find the reason of such behaviour, the inventors found that while the commercially available form was a crystalline form, the in situ formed sodium aluminosilicate was amorphous in nature. It was also seen that even the amorphous form of sodium alumino silicate was not enough as it was not stable and was susceptible to change into the crystalline form at high temperatures. But unexpectedly it was observed that the use of pH quencher according to the first aspect solved this problem.

[0031] It was further a surprising finding of the present invention that when the combination of aluminosilicate and organic filler is used in the amount according to the first aspect of the present invention the soap bars with good hardness and high moisture content could be prepared. It was observed that if the bars were not incorporated with organic filler in the presence of aluminosilicate or the salt of salt of pH quencher, high moisture incorporation was not possible without compromising on the desired bar qualities such as hardness, it was unexpectedly observed that bars as low as 30 TFM could be prepared having good hardness with the compositions according to the present invention.

[0032] It is preferred that in the soap composition of the present invention the SiCh / AhOs mole ratio of the sodium aluminosilicate is in the range of 3: 1 to 1 : 1.

[0033] It is preferred that in the soap composition of the present invention the the soap composition comprises 0.1 to 6 wt% of an electrolyte by weight of the soap composition.

[0034] It is preferred that in the soap composition of the present invention the electrolyte is selected from sodium chloride, sodium sulphate, sodium citrate, or a mixture thereof.

[0035] It is preferred that in the soap composition of the present invention the soap composition comprises an inorganic filler selected from the group of talc, and calcium carbonate.

[0036] It is preferred that in the soap composition of the present invention the soap composition comprises an inorganic filler in the range of 0.1 to 20 wt% by weight of the soap composition.

[0037] It is preferred that in the soap composition of the present invention the iodine value of the soap composition in the range of 30 to 45 g / lodine per 100 g of the soap composition. It is preferred that in the soap composition of the present invention the composition has a pH when measured in a 4% solution with distilled water at 25°C in the range from 9 to 13.

[0038] It is preferred that in the soap composition of the present invention the pH quencher acid is selected from the group of organic acid, polyacrylic acid and dicarboxylic acid.

[0039] It is preferred that in the soap composition of the present invention the organic filler is a starch.

[0040] It is preferred that in the soap composition of the present invention the starch is native starch, pre-gelatinized starch, converted starch, modified starch, combinations or mixtures thereof.

[0041] It is preferred that in the soap composition of the present invention the composition is a soap bar, its density is in the range of 900 - 1200 kg / m3.

[0042] Soap

[0043] When the Total Fatty matter (TFM) in soap composition of the present invention is for personal washing application it comprises 18 to 75 wt% total amount of soap, preferably 20 to 70 wt%, more preferably 25 to 68 wt% and most preferably 25 to 65 wt% by weight of the soap composition. When the soap composition of the invention is for laundering fabrics, it comprises from 15 wt.% to 60 wt.% fatty acid soap. Preferred aspects of such soap compositions comprise at least 20 wt.%, preferably at least 25 wt.%, still preferably at least 30 wt.% and most preferably at least 35 wt.%, but typically not more than 58 wt.%, still preferably not more than 55 wt.%, still further preferably not more than 53 wt.%, still more preferably not more than 50 wt.%, and most preferably not more than 45 wt.% TFM in the soap composition by weight of the soap composition.

[0044] The term total fatty matter is used very widely and popularly in the field of soaps and detergents. The term Total Fatty Matter, abbreviated to "TFM", is used to denote the percentage by weight of fatty acid and triglyceride residues present in the personal wash composition without taking into account the accompanying cations. For a soap having 18 carbon atoms, an accompanying sodium cation will generally amount to about 8 percent by weight. Other cations may be employed as desired, for example zinc, potassium, magnesium, alkyl ammonium and aluminium. The term soap means salt of fatty acid. Preferably, the soap is soap of C8 to C24 fatty acids.

[0045] The cation may be an alkali metal, alkaline earth metal or ammonium ion, preferably alkali metals. Preferably, the cation is selected from sodium or potassium, more preferably sodium. The soap may be saturated or unsaturated. Saturated soaps are preferred over unsaturated soaps for stability. The oil or fatty acids may be of vegetable or animal origin.

[0046] The soap may be obtained by saponification of oils, fats or fatty acids. The fats or oils generally used to make soap compositions may be selected from tallow, tallow stearins, palm oil, palm stearins, soya bean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, babassu oil, and palm kernel oil. The fatty acids may be from coconut, rice bran, groundnut, tallow, palm, palm kernel, cotton seed or soyabean.

[0047] The fatty acid soaps may also be synthetically prepared (e.g. by the oxidation of petroleum or by the hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids, such as those present in tall oil, may also be used. Naphthenic acids may also be used.

[0048] The soap compositions of the present invention preferably include low molecular weight soaps (C8 to C14 soaps) which are generally water soluble, which are in the range of 2 to 20% by weight of the composition. It is preferred that the soap composition includes 15 to 55 wt% of the soap of C16 to C24 fatty acid, which are generally water insoluble soaps. Unsaturated fatty acid soaps preferably at 15 to 42% may also be included in the total soap content of the composition. Unsaturated soaps are preferably oleic acid soaps.

[0049] The soap composition of the present invention comprises from 18 to 75 wt% of TFM. TFM is preferably present in an amount of from 18 to 70 wt%, more preferably 18 to 65 wt%, more preferably 20 to 60 wt%, more preferably 20 to 55 wt% and most preferably 20 to 52 wt%, by weight of the soap composition.

[0050] The soap composition of the invention preferably comprises at least 20 wt.%, preferably at least 25 wt.%, even more preferably at least 30 wt.% and most preferably at least 35 wt.%, but typically not more than 58 wt.%, more preferably not more than 55 wt.%, even more preferably not more than 52 wt.%, and even more preferably not more than 50 wt.%, and most preferably not more than 45 wt.% TFM, by weight of the soap composition. Accordingly, it may preferably comprise from 20 to 58 wt%, more preferably from 20 to 55 wt%, more preferably from 25 to 52 wt%, more preferably from 30 to 50 wt%, more preferably from 35 to 45 wt% TFM, by weight of the soap composition.

[0051] The composition of the invention is preferably free from non-soap surfactant, preferably free from synthetic detergent. It is preferably free from sulfate-type synthetic surfactant, such as for example SLES or SLS. It is preferably free from sulfonate surfactant, such as alkylbenzene sulfonate surfactant, e.g. linear alkylbenzene sulfonates LAS, or branched alkylbenzene sulfonates (BAS), e.g. for sustainability reasons or harshness on the skin. It is preferably free from petroleum-based surfactant, such as for example petryl sulfonates.

[0052] Sodium aluminosilicate

[0053] The composition of the invention comprises selective amount of a sodium aluminosilicate having a specific molar ratio of SiCh / AI2O3. Sodium alumino silicate is preferably included in 2 to 10%, more preferably 2 to 7% by weight of the composition. The sodium aluminosilicate is carefully prepared such that the molar ratio of SiCh / AI2O3 is less than 5.0, preferably equal to or less than 3.5 and most preferably equal to or less than 3.

[0054] It is preferred that the sodium aluminosilicate is prepared in situ, however, it may also be prepared and added at the appropriate stage during the process.

[0055] The present inventors with their extensive research experience in the area of aluminosilicate gels, have been able to develop high moisture soap compositions by incorporating in them, specific aluminosilicate where the SiCh / AI2O3 mole ratio is equal to or less than 3.0. It is preferred that the SiCh / AhOs mole ratio of the polymeric form of sodium aluminosilicate is in the range of 3:1 to 1 :1. It is further preferred that the sodium aluminosilicate is in amorphous form.

[0056] The soap composition of the present invention comprises a pH quencher having pKa value in the range of 3.5 to 6.8, more preferably having pKa value in the range of 4.0 to 5.5 and most preferably having pKa value in the range of 4.5 to 5.0. The pH quencher is selected from the group of salts of organic acid, salt of organic acid, polyacrylic acid, salts of polyacrylic acid, dicarboxylic acid, salts of dicarboxylic acid and mixtures thereof.

[0057] The pH quencher is in the range of 0.1 to 5 wt%, more preferably 1 to 4 wt% and most preferably 1.5 to 3.5 wt% by weight of the soap composition.

[0058] The pH quencher may comprise an acid having pKa value lower than 6.0 along with a salt. It is preferred that when an acid and salt system is used as a pH quencher, corresponding salt of the acid is preferably used.

[0059] When the acid is an organic acid, it may be selected from the group comprising and not limited to citric acid, acetic acid, lactic acid, oxalic acid, tartaric acid, ascorbic acid, maleic acid, maleic anhydrate

[0060] When the acid is a polyacrylic acid, it may be selected from the group comprising and not limited to acrylic polymer acids

[0061] When the acid is a dicarboxylic acid, it may be selected from the group comprising and not limited to adipic acids.

[0062] In an embodiment, the acid form of pH quencher is used as a reactant in making of the soap and the salt form is present in the finished soap composition.

[0063] It was found that the presence of a pH quencher stabilized the alumino silicate in the amorphous form, which benefits the quality of the resulting bars, e.g. in less brittleness and cracking. The invention therefore further relates to the use of a pH quencher acid having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof, preferably in an amount of from 0.1 to 5 wt% , to enhance stabilization of the sodium alumino silicate in amorphous form, when applied in a soap composition according to the invention, i.e.. preferably in a sap composition composition comprising, a. 18 to 75 wt% of total fatty matter; b. 1 .0 to 15.0 wt% of polymeric form of sodium alumino silicate; c. 15 to 45 wt% of water; d. 1 to 45wt% of an organic fillerstarch; and wherein the SiO2 / AI2O3 mole ratio of the polymeric form of sodium alumino silicate is equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form.;

[0064] Preferably, the pH quencher is selected from the group of organic acid, salts of organic acid, polyacrylic acid, salts of polyacrylic acid, dicarboxylic acid, salts of dicarboxylic acid, and mixtures thereof. More preferably, the pH quencher is selected from the group of salts of organic acid, polyacrylic acid, salts of polyacrylic acid, dicarboxylic acid, salts of dicarboxylic acid, and mixtures thereof.

[0065] Water

[0066] The soap compositions of the present invention can hold high amount of moisture or water content. The soap compositions of the present invention have 15 to 45 wt% of water, preferably 20 to 40 wt%, more preferably 22 to 40wt% and most preferably 25 to 40wt% of water by weight of the soap composition.

[0067] Electrolyte

[0068] Inclusion of small amount of an electrolyte (other than soap) can influence the liquid and solid phase ratio. Increasing the electrolyte content lowers the solubility of soap thereby increasing the solid phase amount, on the other hand lowering the electrolyte levels make the bars softer.

[0069] The soap composition generally comprises electrolyte and water. Electrolytes as per this invention include compounds that substantially dissociate into ions in water. Electrolytes as per this invention are not an ionic surfactant. Suitable electrolytes for inclusion in the soap making process are alkali metal salts. Preferred electrolytes include sodium sulfate, sodium chloride, sodium citrate, potassium chloride, potassium sulfate, sodium carbonate and other mono or di or tri salts of alkaline earth metals, more preferred electrolytes are sodium chloride, sodium sulfate, potassium chloride and especially preferred electrolytes are sodium chloride and sodium sulfate and combinations thereof. For the avoidance of doubt is clarified that the electrolyte is a non-soap material. For the avoidance of doubt, it is clarified that the electrolyte is a non-soap material. The soap composition of the present invention may comprise an electrolyte in the range of 0.1 to 6 wt% of the weight of composition, more preferably 0.5 to 5 and most preferably 0.7 to 4 wt%.

[0070] It is most preferred that sodium sulphate and sodium chloride are used as electrolytes for the composition of the present invention.

[0071] It is preferred that sodium sulphate is present in the range of 0.1 to 6 wt% of the weight of composition, more preferably 0.5 to 5 and most preferably 0.7 to 4 wt%. It is preferred that sodium sulphate is at least 0.1 wt%, more preferably at least 0.5wt%, and most preferably at least 0.7 wt% and it is preferred that it is not more than 6wt%, more preferably not more than 5 wt%, furthermore preferably not more than 4 wt% and most preferably not more than 3.5wt% of the total weight of composition of the present invention.

[0072] It is preferred that when sodium chloride is present in the range of 0.1 to 6 wt% of the weight of composition, more preferably 0.5 to 5 and most preferably 0.7 to 4 wt%. It is preferred that sodium chloride is at least 0.1 wt%, more preferably at least 0.5wt%, and most preferably at least 0.7 wt% and it is preferred that it is not more than 6wt%, more preferably not more than 5 wt%, furthermore preferably not more than 4 wt% and most preferably not more than 3.5 wt% of the total weight of composition of the present invention.

[0073] Organic filler

[0074] It is preferred that the organic filler is a starch and preferably the starch is a native starch, pregelatinized starch, converted starch or its mixture.

[0075] It is preferred that the organic filler in the soap composition ranges from 1 to 45 wt%, more preferably from 2 to 40 wt% and most preferably from 3 to 35wt% by weight of the soap composition.

[0076] It is preferred that when the organic filler is starch, the starch in the soap composition ranges from 1 to 45 wt%, more preferably from 2 to 40 wt% and most preferably from 3 to 35wt%. More preferably the composition comprises 5 to 45 wt%, even more preferably 5 to 40 wt%, even more preferably 6 to 40, even more preferably 8 to 40 wt%, even more preferably 10 to 40 wt%, even more preferably 12 to 35 wt% of starch, based on the weight of the composition.

[0077] Suitable starch materials include natural starch (from corn, wheat, rice, potato, tapioca and the like), pre-gelatinized starch, various physically and chemically modified starch and mixtures thereof. By the term natural starch is meant starch which has not been subject to chemical or physical modification - also known as raw or native starch.

[0078] A preferred starch is natural or native starch from maize (corn), cassava, wheat, potato, rice and other natural sources of it. Raw starch with different ratio of amylase and amylopectic: e.g. maize (25% amylase); waxy maize (0%); high amylase maize (70%); potato (23%); rice (16%); sago (27%); cassava (18%); wheat (30%) and others. The raw starch can be used directly or modified during the process of making the bar composition such that the starch becomes gelatinized, either partially or fully gelantinized.

[0079] Suitable starchy materials which may be used include natural starch (from corn, wheat, rice, potato, tapioca and the like), pregelatinzed starch, various physically and chemically modified starch and mixtures thereof. By the term natural starch is meant starch which has not been subjected to chemical or physical modification - also known as raw or native starch. The raw starch can be used directly or modified during the process of making the bar composition such that the starch becomes gelatinized, either partially or fully gelatinized. Such starchy materials are commercially available e.g. FARMAL® CS 3400 (corn starch) and FARMAL® WS 4400 (corn starch; waxy unmodified).

[0080] It is preferred that the organic filler is a starch and preferably the starch is a native starch, pregelatinized starch, converted starch or its mixture.

[0081] Non-soap surfactant

[0082] In addition to the soap of fatty acids, preferred bars may include a non-soap surfactant, which acts as a co-surfactant and which is selected from anionic, non-ionic, zwitterionic, amphoteric and cationic surfactants. Preferred bars include 0.0001 to 15 wt% co-surfactants based on the weight of the composition. More preferred bars include 2 to 10 wt% co-surfactant and most preferred compositions include 2.5 to 6 wt% co-surfactant based on the weight of the composition. Suitable anionic surfactants include water soluble salts of organic sulphuric reaction products having in the molecular structure an alkyl radical containing from 8 to 22 carbon atoms, and a radical chosen from sulphonic acid or sulphuric acid ester radicals, and mixtures thereof.

[0083] Examples of suitable anionic surfactants are sodium and potassium alcohol sulphates, especially those obtained by sulphating the higher alcohols produced by reducing the glycerides of tallow 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 sulphates, especially those ethers of the higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulphates; sodium and potassium salts of sulphuric 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 ether sulphate with from 1 to 8 units of ethylene oxide molecule 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. The preferred water-soluble synthetic anionic surfactants are the alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of higher alkyl benzene sulphonates and mixtures with olefin sulphonates and higher alkyl sulphates, and the higher fatty acid monoglyceride sulphates.

[0084] Suitable non-ionic surfactants can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature.

[0085] The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield 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 coconut oil ethylene oxide condensate having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols whose alkyl group 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 ethylenediamine and propylene oxide with ethylene oxide, the condensate containing from 40 to 80 percent of polyoxyethylene radicals by weight and having a molecular weight of from 5,000 to 11 ,000; tertiary amine oxides of structure R3NO, where one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl groups, for instance dimethyldodecylamine oxide; tertiary phosphine oxides of structure R3PO, where one group R is an alkyl group of from 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylphosphine oxide; and dialkyl sulphoxides of structure R2SO where the group R is an alkyl group of from 10 to 18 carbon atoms and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide; fatty acid alkylolamides; alkylene oxide condensates of fatty acid alkylolamides and alkyl mercaptans.

[0086] Suitable cationic surfactants that can be incorporated are alkyl substituted quarternary ammonium halide salts e.g. bis (hydrogenated tallow) dimethylammonium chlorides, cetyltrimethyl ammonium bromide, benzalkonium chlorides and dodecylmethylpolyoxyethylene ammonium chloride and amine and imidazoline salts for e.g. primary, secondary and tertiary amine hydrochlorides and imidazoline hydrochlorides.

[0087] Suitable amphoteric surfactants 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 water-solubilising group, for instance sodium 3- dodecylamino-propionate, sodium 3- dodecylaminopropane sulphonate and sodium N- 2-hydroxydodecyl-N- methyltaurate.

[0088] Suitable zwitterionic surfactants are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilising group, for instance 3-(N-N-dimethyl-N- hexadecylammonium) propane-1 -sulphonate betaine, 3-(dodecylmethyl sulphonium) propane-1 -sulphonate betaine and 3- (cetylmethylphosphonium) ethane sulphonate betaine.

[0089] Further examples of suitable detergent-active compounds are compounds commonly used as surface-active agents given in the well-known textbooks "Surface Active Agents", Volume I by Schwartz and Perry and "Surface Active Agents and Detergents", Volume II by Schwartz, Perry and Berch.

[0090] In addition to the ingredients described earlier, preferred cleansing bar may include other ingredients. A preferred bar may include up to 30 wt% benefit agents. Preferred benefit agents are moisturizers, emollients, sunscreens and anti-ageing compounds. The agents may be added at an appropriate step during the process of making the bars. Some benefit agents may be introduced as macro domains.

[0091] Examples of moisturizers and humectants include cetyl alcohol, CARBOPOL® 934, ethoxylated castor oil, paraffin oils, lanolin and its derivatives. Silicone compounds such as silicone surfactants like DC ®3225C (Dow Corning) and / or silicone emollients, silicone oil (DC-200 ® ex. Dow Corning) may also be included. Sunscreens such as 4- tertiary butyls'methoxy dibenzoylmethane (available under the trade name PARSOL ® 1789 from Givaudan) or 2-ethyl hexyl methoxy cinnamate (available under the trade name PARSOL ®MCX from Givaudan) or other UV-A and UV-B sun-screens may also be added. Lipids such as cholesterol, ceramides, and pseudoceramides, and exfoliant particles such as polyethylene beads, walnut shells, apricot seeds, flower petals and seeds may also be present. Structurants such as maltodextrin or starch may be used to structure the bars. Preferred bars may also include essential oils such as bergamot and citrus or insoluble extracts of avocado, grape, grapeseed, myrrh, cucumber, watercress, calendula, elder flower, geranium, linden blossom, amaranth, seaweed, gingko, ginseng and other plant extracts. Further optional ingredients include chelating agents such as ethylene diamine tetra acetic acid, preservatives (e.g. GLYDANT ®) antioxidants, and natural and synthetic perfumes. Cationic polymers may be included as conditioners. These include POLYQUATERNIUM ® , MERQUAT ® polymers, and JAGUAR ® polymers. The composition can also optionally include other ingredients conventionally used in soap such as lather boosters, hemectants such as glycerine, moisturisers, colourants and opacifiers.

[0092] Other adjunct materials may include germicides and preservatives. These ingredients normally will be in amounts less than 2 wt%, usually less than 0.5 wt%. Other optional ingredients like anti-oxidants, perfumes, polymers, chelating agents, colourants, deodorants, dyes, emollients, moisturizers, enzymes, foam boosters, germicides, antimicrobials, lathering agents, pearlescers, skin conditioners, stabilisers, superfatting agents, sunscreens may be added in suitable amounts in the process of the invention. Preferably, the ingredients are added after the saponification step and before filtering. Sodium metabisulphite, ethylene diamine tetra acetic acid (EDTA), borax and ethylene hydroxy diphosphonic acid (EHDP) are preferably added to the formulation. It is preferred that the cleansing bar has no or essentially no opacifiers. By opacifiers is meant compounds which limit the quantity of light passing through the solid composition. When opacifiers are present, the solid composition is generally opaque, i.e. "opacification". Examples of opacifiers include titanium dioxide, zinc oxide and the like.

[0093] Optional ingredients in soap compositions

[0094] The soaps bar composition may optionally comprise 0.1 to 15%, preferably 0.2 to 12% by weight of free fatty acids. By free fatty acids is meant a carboxylic acid comprising a hydrocarbon chain and a terminal carboxyl group bonded to an H. Suitable fatty acids are C8 to C22 fatty acids. Preferred fatty acids are C12 to C18, preferably predominantly saturated, straight-chain fatty acids. However, some unsaturated fatty acids can also be employed.

[0095] The composition preferably comprises a polyhydric alcohol (also called polyol) or mixture of polyols. Polyol is a term used herein to designate a compound having multiple hydroxyl groups (at least two, preferably at least three) which is highly water soluble. Many types of polyols are available including: relatively low molecular weight short chain polyhydroxy compounds such as glycerol and propylene glycol; sugars such as sorbitol, manitol, sucrose and glucose; modified carbohydrates such as hydrolyzed starch, dextrin and maltodextrin, and polymeric synthetic polyols such as polyalkylene glycols, for example polyoxyethylene glycol (PEG) and polyoxypropylene glycol (PPG). Especially preferred polyols are glycerol, sorbitol and their mixtures. Most preferred polyol is glycerol. In a preferred embodiment, the composition, e.g. bars, of the invention comprise 0 to 8%, preferably 1 to 7.5%, more preferably 1 to 6.5 and even more preferably 1 to 5.5% by wt. polyol. Glycerol, if present, is preferably present in an amount of from 0 to 8%, preferably 1 to 7.5%, more preferably 1 to 6.5 and even more preferably 1 to 5.5%, and even more preferably from 1 to 5 %, by wt. based on the weight of the soap composition.

[0096] The various optional ingredients that make up the final soap composition are as described below:

[0097] The total level of the adjuvant materials used in the bar composition generally is in an amount not higher than 50%, preferably 1 to 50%, more preferably 3 to 45% by wt. of the soap composition. The adjuvant system may optionally include insoluble particles comprising one or a combination of materials. By insoluble particles is meant materials that are present in solid particulate form and suitable for personal washing. Preferably, there are mineral (e.g., inorganic) or organic particles.

[0098] The insoluble particles should not be perceived as scratchy or granular and thus should have a particle size less than 300 microns, more preferably less than 100 microns and most preferably less than 50 microns.

[0099] Preferred inorganic particulate material may be inorganic fillers, including but not limited to talc, clay and calcium carbonate. Talc is a magnesium silicate mineral material, with a sheet silicate structure and a composition of Mg3Si4(OH)22 and may be available in the hydrated form. It has a plate-like morphology, and is essentially oleophilic / hydrophobic, i.e. , it is wetted by oil rather than water.

[0100] Calcium carbonate or chalk exists in three crystal forms: calcite, aragonite and vaterite. The natural morphology of calcite is rhombohedral or cuboidal, acicular or dendritic for aragonite and spheroidal for vaterite.

[0101] Examples of other optional insoluble inorganic particulate materials include aluminates, silicates, phosphates, insoluble sulfates, borates and clays (e.g., kaolin, china clay) and their combinations.

[0102] Organic particulate materials include: insoluble polysaccharides such as highly crosslinked or insolubilized starch (e.g., by reaction with a hydrophobe such as Octyl succinate) and cellulose; synthetic polymers such as various polymer lattices and suspension polymers; insoluble soaps and mixtures thereof. It may be preferred, that the composition is free from insoluble polysaccharides, e.g. is free from insoluble starch. The composition of the invention may alternatively be free from soluble organic polymers other than starch and surfactant, e.g. it may be preferred that it is free from carboxymethyl cellulose.

[0103] It is preferred that the compositions of the invention comprise polymers. Polymers of the acrylate class are especially preferred. Preferred bars include 0.05 to 5% acrylates. More preferred bars include 0.01 to 3% acrylates. Examples of acrylate polymers include polymers and copolymers of acrylic acid crosslinked with polyallylsucrose as described in US Patent 2,798,053 which is herein incorporated by reference. Other examples include polyacrylates, acrylate copolymers or alkali swellable emulsion acrylate copolymers, hydrophobically modified alkali swellable copolymers, and crosslinked homopolymers of acrylic acid. Examples of such commercially available polymers are: ACLILYN®, CARBOPOL®, and CARBOPOL® Ultrez grade series. It may however be also preferred in other cases that the composition of the invention is free from polymers of the acrylate class, e.g. from polyacrylates.

[0104] Bar compositions preferably comprise 0.1 to 25% by wt. of bar composition, preferably 5 to 15 by wt. of these mineral or organic particles.

[0105] An opacifier may be optionally present in the personal care composition. When opacifiers are present, the cleansing bar is generally opaque. Examples of opacifiers include titanium dioxide, zinc oxide and the like. A particularly preferred opacifier that can be employed when an opaque soap composition is desired is ethylene glycol mono- or di-stearate, for example in the form of a 20% solution in sodium lauryl ether sulphate. An alternative opacifying agent is zinc stearate.

[0106] The product can take the form of a water-clear, i.e. transparent soap, in which case it will not contain an opacifier.

[0107] In the soap composition of the present invention the composition has a pH when measured in a 4% solution with distilled water at 25°C in the range from 9 to 13.

[0108] A preferred bar may additionally include up to 30 wt% benefit agents. Preferred benefit agents include moisturizers, emollients, sunscreens and anti-ageing compounds. The agents may be added at an appropriate step during the process of making the bars. Some benefit agents may be introduced as macro domains.

[0109] Other optional ingredients like anti-oxidants, perfumes, polymers, chelating agents, colourants, deodorants, dyes, enzymes, foam boosters, germicides, anti-microbials, lathering agents, pearlescers, skin conditioners, stabilizers or superfatting agents, may be added in suitable amounts in the process of the invention. Preferably, the ingredients are added after the saponification step. Sodium metabisulphite, ethylene diamine tetra acetic acid (EDTA), borax or ethylene hydroxy diphosphonic acid (EHDP) are preferably added to the formulation. The composition of the invention could be used to deliver antimicrobial benefits. Antimicrobial agents that are preferably included to deliver this benefit include oligodynamic metals or compounds thereof. Preferred metals are silver, copper, zinc, gold or aluminium. Silver is particularly preferred. In the ionic form it may exist as a salt or any compound in any applicable oxidation state. Preferred silver compounds are silver oxide, silver nitrate, silver acetate, silver sulfate, silver benzoate, silver salicylate, silver carbonate, silver citrate or silver phosphate, with silver oxide, silver sulfate and silver citrate being of particular interest in one or more embodiments. In at least one preferred embodiment the silver compound is silver oxide. Oligodynamic metal or a compound thereof is preferably included in 0.0001 to 2%, preferably 0.001 to 1% by weight of the composition. Alternately an essential oil antimicrobial active may be included in the composition of the invention. Preferred essential oil actives which may be included are terpineol, thymol, carvacol, (E) -2(prop-1-enyl) phenol, 2- propylphenol, 4- pentylphenol, 4-sec-butylphenol, 2-benzyl phenol, eugenol or combinations thereof. Furthermore, preferred essential oil actives are terpineol, thymol, carvacrol or thymol, most preferred being terpineol or thymol and ideally a combination of the two. Essential oil actives are preferably included in 0.001 to 1%, preferably 0.01 to 0.5% by weight of the composition.

[0110] In soap compositions for laundering fabric, one or more of the above described optional ingredients may be included. However, in laundry bars, antimicrobial agents are generally not added. Laundry bars generally include chelating agents that are generally not included in soap compositions for personal cleansing. Chelating agents may be selected from but not limited to ethylene diamine tetra acetic acid (EDTA), ethylene hydroxy diphosphonic acid (EH DP) or mixtures thereof. The chelating agent is preferably present in an amount ranging from 0.01 wt.% to 1 wt.%. Non-phosphate chelating agents like methylglycinediacetic acid and salts thereof are also preferred.

[0111] Process

[0112] In a second aspect, the present invention relates to the present invention relates to process comprising the steps of: a. saponifying a fatty matter with an alkali to produce a saponified mass; b. adding sodium aluminate, sodium silicate, and an acid having pKa value between 3.5 to 6.8 and mixing or corresponding salt of the acid or combination thereof; and c. adding 1 to 45wt% organic fillers to step (b) by weight of the resulting soap composition to obtain a mixture; and d. extruding the mixture of step (c) to obtain a desired soap composition according to the first aspect; wherein water is added at any of the steps (a), (b) or (c).

[0113] The soap composition may be made into a bar by a press that first involves saponification of the fat charge with alkali followed by extruding the mixture in a conventional plodder. The plodded mass may then be optionally cut to a desired size and stamped with a desirable indicia. An especially important benefit of the present invention is that, notwithstanding the high amount of water content of the soap composition, compositions thus prepared by extrusion are found to be easy to stamp with a desirable indicia. By “easy to extrude” is meant that the hardness of the bar as it is extruded is high enough that it exits the extruder in a firm enough form that it can be called a rigid bar. The hardness of the bar is preferably higher than 1.2 kg, more preferably in the range of 1.2 to 5.0 kg (at 40°C). The hardness is preferably measured using the TA-XT Express apparatus available from Stable Micro Systems. The hardness is measured using this apparatus with a 30° conical probe - Part #P / 30c to a penetration of 15 mm. If the soap mass is too soft and is passed through the extruder it will not extrude out of the extruder in a cohesive enough mass to be called a bar. By “easy to stamp” is meant that the soap composition is of such a consistency and low enough stickiness that it does not stick to the die that is used to stamp any desired indicia on the bar. The soap composition prepared by the process of the invention therefore preferably comprises an indicium stamped thereupon.

[0114] The specific process that may be employed using the above described general process for soap composition manufacture comprises one of the following processes.

[0115] In another preferred aspect, the process to prepare the soap composition of the present invention comprises the steps of (a) preparing soap in a plough shear mixer or crutcher by reacting desired amount of fatty acid / oil with alkali at 90 to 110°C; (b) including sodium aluminosilicate in the plough shear mixer or crutcher to mix with the soap so formed in step (a) to prepare a mixture; (c) providing a pH quencher having pKa value between 4 to 6.8; (d) spray drying the mixture or passing it through a triple roll mill; and (e) then passing it though a plodder to prepare the desired soap composition. In yet another aspect, preferably, the process to prepare the soap composition of the present invention comprises the steps of (a) preparing the sodium alumino silicate is in situ in a plough shear mixer or crutcher by reacting the desired amount of sodium aluminate with sodium silicate; followed by (b) preparing soap in the same plough shear mixer or crutcher by reacting desired amount of fatty acid / oil with alkali at 90 to 110°C with constant agitation to prepare a mixture; (c) providing a pH quencher having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof; (d) spray drying the mixture or passing it through a triple roll mill; and (e) then passing it though a plodder to prepare the desired soap composition.

[0116] It is preferred that in the process of the present invention the TFM of soap composition is in the range of 18 to 75%.

[0117] It is preferred that in the process of the present invention the sodium aluminosilicate is in the range of 1.0 to 15 wt%, more preferably in the range of 1.5 to 10wt% of the weight of soap composition.

[0118] It is preferred that in the process of the present invention the soap composition comprises 15 to 45 wt% water by weight of the soap composition.

[0119] It is preferred that in the process of the present invention the soap composition comprises 0.1 to 6 wt% of an electrolyte by weight of the soap composition.

[0120] It is preferred that in the process of the present invention the soap composition, the organic filler is present in the range of 1 to 45wt% by weight of the soap composition.

[0121] It is preferred that in the process of the present invention the electrolyte is selected from sodium chloride, sodium sulphate, sodium citrate or a mixture thereof.

[0122] It is preferred that in the process of the present invention sodium aluminosilicate is formed in situ.

[0123] It is preferred that the soap composition of the present invention is prepared in a plough shear mixer. The sodium aluminosilicate and the various methods by which it can be prepared and incorporated in the soap is described below.

[0124] Sodium aluminosilicate is prepared by reacting sodium silicate and sodium aluminate in aqueous medium. This can be prepared separately in a mixer for incorporation in the soap. Such a process is known as premade route. Alternately sodium alumino silicate can be prepared in the same process step (and reactor) where the saponification of soap takes place and such a process is known as the in-situ route. Alumino silicate could be incorporated or made in situ in any of the soap processing equipment known in the art e.g., sigma mixer, plough shear mixer, or the crutcher. Preferred processes by which aluminosilicate is incorporated in soap in the present invention are detailed below:

[0125] Method 1 (Pre-made route):

[0126] In this method aluminosilicate is prepared separately and added to the soap either during the stage of saponification of oil (or fatty acids) or during the finishing line.

[0127] Gel preparation:

[0128] The required amount of sodium silicate and water is taken in a container under mixing at about 250-300 rpm. Calculated amount of aqueous sodium aluminate is slowly added under mixing condition. The mixing may be continued for about 15 minutes.

[0129] Extrusion of soap with the premade sodium aluminosilicate:

[0130] The premade sodium aluminosilicate can be added to the soap after complete saponification of oil (or neutralization of fatty acids) in the plough shear mixer (PSM) / Crutcher or in the finishing line (e.g. I the sigma mixer). The mass is then milled through a triple roll mill. The mass is then added to the plodder to extrude the soap in the shape of a billet.

[0131] Method 2 (in-situ route):

[0132] In this route sodium aluminosilicate is prepared in the soap making equipment e.g., in the PSM, the crutcher, or the sigma mixer. In-situ route in PSM / Crutcher:

[0133] The required amount of fatty acids / oil blend is taken in a PSM / Crutcher and then it is heated to about 90 to 110°C and it is neutralized by adding stoichiometric amount of alkali. Prediluted aqueous solution of sodium silicate is added and allowed to mix for some time. Thereafter, aqueous solution of sodium aluminate is added slowly under mixing conditions and a pH quencher having pKa value between 3.5 to 6.8, or its corresponding salt or combination thereof is added. The soap mass is then taken out of the mixer and passed through either a triple roll mill if the mass come from a PSM or spray dried if the mass comes from a crutcher. The mass is then passed into a plodder to extrude the soap in the shape of a billet.

[0134] An alternate route to prepare this is as follows. Required amount of sodium silicate and water are taken in a PSM / Crutcher and required amount of sodium aluminate is added slowly under mixing conditions for some time. Thereafter required amount of fatty acids / oil blend is taken into it and neutralized by adding stoichiometric amount of alkali for desired amount of time of mixing. The mass is then taken out and spray dried or passed through a triple roll mill before passing through a plodder to get the mass in the shape of a bar.

[0135] Preparation of the sodium aluminosilicate

[0136] The sodium aluminosilicate can be prepared separately (calling it as ex-situ or premade) and can also be prepared in the presence of soap (calling it as in-situ).

[0137] Specific example of preparation of ex-situ sodium aluminosilicate:

[0138] To prepare a sodium aluminosilicate of SiO2 / AI2O3 mole ratio 2.05 following sequence of addition and conditions are followed:

[0139] Required quantity (1083gm as 45% aqueous solution) of sodium silicate solution is taken in a 5 litre plastic beaker. Required quantity (2103gm) of process water was added slowly under stirring condition (350 rpm) using an overhead stirrer. Required quantity (1083 gm as 45% aqueous solution) of sodium aluminate solution was added slowly into the prediluted aqueous solution of sodium silicate keeping stirrer on. The aqueous mixture is allowed to mix for another 5 min at high speed (500 rpm). EXAMPLES

[0140] Example 1- Soap Compositions

[0141] The soap compositions for the examples were prepared in accordance with the present invention.

[0142] To process the high moisture Z-Gel noodle a 35kg soap was prepared in plough shear mixer. Then the mass was converted into the form of noodle, extruding through plodder. To prepare the 35 kg high moisture soap mass the fatty acids were melted at 65-70°C in a fat melting tank; plough shear was heated and maintained at 80°C by jacket oil heater; the mixer was switched on and the plough and chopper were kept in the rotating stage; the required amount of melted fatty acids and -48% caustic acid solution were poured from two different tank into the mixer in 3:1 weight ratio. The electrolytes were then added (e.g., NaCI, Na2SO4) in the form of solution. After complete saponification the chelating ingredients were added and free alkalinity was checked and maintained less than 0.1 wt%. A prediluted sodium silicate by the process water was added and allowed to mix for a few minutes. 45 wt% of sodium aluminate solution was added and allowed to mix for a minute. Citric acid buffer was added and allowed to mix for 2 minutes. The mass from the PSM was dropped and milled through triple roll miller. The miller output mass was kept below 50°C and the milled mass was plodded and converted into the shape of noodle by extruding through a noodler plate.

[0143] The soap bars were prepared in accordance with the soap compositions of the present invention.

[0144] To convert the aluminosilicate containing high moisture noodle into soap bar following steps were followed. The mixing was carried out in sigma mixer and milling operation was performed through triple roll mixer by passing the sigma mixer mass. The milled mass was plodded through a twin stage plodder and the mass was extruded in the shape of billet and 500-550 mmHg vacuum was maintained.

[0145] The hardness of the soap bars was measured by a TAXT meter and simultaneously the billet temperature was taken by inserting a temperature probe into it. The billets were then stamped in a pneumatic stamper and the bars were taken out from the stamper cavity. The hardness of the samples was measured using the protocol given below.

[0146] A hardness value of at least 1.2 kg (measured at 40°C), preferably at least 2.7 kg is acceptable.

[0147] Table 1

[0148] The data of table 1 gives examples of soap bars E4 to E6 prepared according to the present invention. E1 is a high TFM control soap bar with low moisture content. E2 is a control without sodium aluminosilicate but having starch. It is observed that in E2, in the absence of sodium aluminosilicate, the inventors were not able to increase the moisture content of the soap bars beyond 16% to obtain stampable soap bars. In E3 control sample, when the salt of pH quencher was absent, it was observed that soap composition was not hard enough to be processed. Whereas the soap bars E4 to E6 when prepared according to the present invention could be formulated with high moisture content such as 23 wt% by weight of the soap composition. It was unexpected finding of the inventors that bars as low as 30TFM could be prepared having good hardness with the compositions according to the present invention.

[0149] The data in Table 1 indicate that soap compositions with high moisture content can be prepared as per the present invention which extrude well and have high hardness.

[0150] Example 2- Performance of soaps with in situ generated sodium alumino silicate with commercially available Zeolite 4A

[0151] In this example the sodium alumino silicate was generate in situ, and compared with the commercially available Zeolite 4A for soap bars made according to Example 1. A comparison was made to check the performance difference of the soap bars made from the composition of the present invention, E7 and that made with commercially available Zeolite 4A (Metro Chem Industries) E8 and E9.

[0152] The solid-state structure of the material in the soap bar matrix was confirmed by XRD study using (Ultima IV) XRD instrument. The XRD data showed no peaks sharp peak for compositions E7 and clear crystalline peaks for composition E8 and E9, thereby confirming that the aluminosilicate is amorphous form, whereas the Zeolite 4A is known to be a crystalline form.

[0153] Upon further experimentation with the pre-formed amorphous form of sodium alumino silicate it was further confirmed that the form of sodium alumino silicate plays a role in better soap bar properties.

[0154] Table 4- Effect of forms of different forms of sodium alumino silicate

[0155] The data very clearly show that when similar soap bars were attempted to be made with same amount of moisture levels, all forms of sodium alumino silicate do not work equally well and the form of sodium alumino silicate is an important factor in the qualities of the resultant soap bar. The data show that when same amount of crystalline form of sodium alumino silicate is used the resultant bar could not be plodded whereas when higher amount of crystalline form of sodium alumino silicate is used the bar could not be plodded but the hardness is not comparable to that of the bar of the present invention and efflorescence was also seen quickly within 3 months. Whereas in the soap bar prepared according to the present invention (E7) showed no efflorescence even upto 1 year.

[0156] Therefore, it was surprising finding of the inventors of the present invention that even the form of sodium alumino silicate used was important for the properties of the resultant soap bar the inventors found that the soap bars with amorphous form of sodium alumino silicate performed much better to contribute towards the hardness property of the soap bar and this form is weight efficient than the crystalline form was used and no efflorescence was seen for even a year.

[0157] Hardness Testing Protocol

[0158] Principle

[0159] A 30° conical probe penetrates into a soap / syndet sample at a specified speed to a predetermined depth. The resistance generated at the specific depth is recorded. There is no size or weight requirement of the tested sample except that the bar / billet be bigger than the penetration of the cone (15mm) and have enough area. The recorded resistance number is also related to the yield stress and the stress can be calculated as noted below. The hardness (and / or calculated yield stress) can be measured by a variety of different penetrometer methods. In this invention, as noted above, we use probe which penetrates to depth of 15 mm.

[0160] Apparatus and Equipment

[0161] TA-XT Express (Stable Micro Systems)

[0162] 30° conical probe - Part #P / 30c (Stable Micro Systems)

[0163] Sampling Technique

[0164] This test can be applied to billets from a plodder, finished bars, or small pieces of soap / syndet (noodles, pellets, or bits). In the case of billets, pieces of a suitable size (9 cm) for the TA-XT can be cut out from a larger sample. In the case of pellets or bits which are too small to be mounted in the TA-XT, the compression fixture is used to form several noodles into a single pastille large enough to be tested.

[0165] Procedure

[0166] Setting up the TA-XT Express

[0167] These settings need to be inserted in the system only once. They are saved and loaded whenever the instrument is turned on again. This ensures settings are constant and that all experimental results are readily reproducible.

[0168] Set test method

[0169] Press MENU

[0170] Select TEST SETTINGS (Press 1) Select TEST TPE (Press 1)

[0171] Choose option 1 (CYCLE TEST) and press OK

[0172] Press MENU

[0173] Select TEST SETTINGS (Press 1)

[0174] Select PARAMETERS (Press 2)

[0175] Select PRE TEST SPEED (Press 1)

[0176] Type 2 (mm s-1) and press OK

[0177] Select TRIGGER FORCE (Press 2)

[0178] Type 5 (g) and Press OK

[0179] Select TEST SPEED (Press 3)

[0180] Type 1 (mm s-1) and press OK

[0181] Select RETURN SPEED (Press 4)

[0182] Type 10 (mm s-1) and press OK

[0183] Select DISTANCE (Press 5)

[0184] Type 15 (mm) for soap billets or 3 (mm) for soap pastilles and press OK

[0185] Select TIME (Press 6)

[0186] Type 1 (CYCLE)

[0187] Calibration

[0188] Screw the probe onto the probe carrier.

[0189] Press MENU

[0190] Select OPTIONS (Press 3)

[0191] Select CALIBRATE FORCE (Press 1) - the instrument asks for the user to check whether the calibration platform is clear

[0192] Press OK to continue and wait until the instrument is ready.

[0193] Place the 2kg calibration weight onto the calibration platform and press OK

[0194] Wait until the message “calibration completed” is displayed and remove the weight from the platform.

[0195] Sample Measurements

[0196] Place the billet onto the test platform.

[0197] Place the probe close to the surface of the billet (without touching it) by pressing the UP or

[0198] DOWN arrows.

[0199] Press RUN Take the readings (g or kg) at the target distance (Fin).

[0200] After the run is performed, the probe returns to its original position.

[0201] Remove the sample from the platform and record its temperature.

[0202] Calculation & Expression of Results

[0203] Output

[0204] The output from this test is the readout of the TA-XT as “force” (RT) in g or kg at the target penetration distance, combined with the sample temperature measurement. (In the subject invention, the force is measured in Kg at 40°C at 15 mm distance)

[0205] The force reading can be converted to extensional stress, according to the equation given below.

[0206] The equation to convert the TX-XT readout to extensional stress is where: o = extensional stress

[0207] C = "constraint factor" (1.5 for 309cone)

[0208] Gc= acceleration of gravity ,r

[0209] A = projected area of cone = d = penetration depth 0 = cone angle

[0210] For a 30° cone at 15 mm penetration, Equation 2 becomes ct (Pa) = RT(g) x 128.8

[0211] This stress is equivalent to the static yield stress as measured by penetrometer. The extension rate is: where E = extension rate (s-1)

[0212] V = cone velocity

[0213] For a 30° cone moving at 1mm / s, E = 0.249 s-1 Temperature Correction

[0214] The hardness (yield stress) of skin cleansing bar formulations is temperature-sensitive. For meaningful comparisons, the reading at the target distance (RT) should be corrected to a standard reference temperature (normally 40°C), according to the following equation:

[0215] R40 = RT x exp[a(T-40)] where R40 = reading at the reference temperature (40°C)

[0216] RT = reading at the temperature T a = coefficient for temperature correction T = temperature at which the sample was analyzed.

[0217] The correction can be applied to the extensional stress.

[0218] The result is the temperature-corrected force or stress, but it is advisable to record the instrument reading and the sample temperature also.

Claims

Claims1 . A soap composition comprising, a. 18 to 55 wt% of total fatty matter; b. 1.0 to 15.0 wt% of polymeric form of sodium alumino silicate; c. 15 to 45 wt% of water; d. 5 to 45wt% of starch; and e. 0.1 to 5 wt% of a pH quencher having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof; wherein the SiCh / AhCh mole ratio of the polymeric form of sodium alumino silicate is equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; and wherein the pH quencher is selected from the group of, polyacrylic acid, salts of polyacrylic acid, dicarboxylic acid, salts of dicarboxylic acid; organic acid, salts of organic acid, and mixtures thereof.

2. A soap composition according to claim 1 , wherein the SiCh / AhOs mole ratio of the polymeric form of sodium alumino silicate is in the range of 3: 1 to 1 :1.

3. A soap composition according to claims 1 or 2, wherein the soap composition comprises 0.1 to 6 wt% of an electrolyte by weight of the soap composition.

4. A soap composition according to claims 3, wherein the electrolyte is selected from sodium chloride, sodium sulphate, sodium citrate, or a mixture thereof.

5. A soap composition according to any one of the preceding claims from 1 to 4, wherein the soap composition comprises an inorganic filler selected from the group of talc, and calcium carbonate.

6. A soap composition according to any one of the preceding claims from 1 to 5, wherein the soap composition comprises an inorganic filler in the range of 0.1 to 20 wt% by weight of the soap composition.

7. A soap composition according to any one of the preceding claims from 1 to 6, wherein the soap composition has an iodine value in the range of 30 to 45 g / lodine per 100 g of the soap composition.

8. A soap composition according to any one of the preceding claims from 1 to 7, wherein the composition has a pH when measured in a 4% solution with distilled water at 25°C in the range from 9 to 13.

9. A soap composition according to any one of the preceding claims from 1 to 8, wherein the starch is native starch, pre-gelatinized starch, converted starch, modified starch, or mixtures thereof.

10. A soap composition according to any one of the preceding claims from 1 to 9, wherein, when the composition is a soap bar, its specific gravity density is in the range of 1.02 to 1.1.

11. A process to prepare a soap composition according to any one of the preceding claims from 1 to 10, the process comprising the steps of: a. saponifying a fatty matter with an alkali to produce a saponified mass; b. adding sodium aluminate, sodium silicate, and an acid having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof, and mixing; c. adding 1 to 45% organic fillers comprising starch by weight of the resulting soap composition to step (b) to obtain a mixture; and d. extruding the mixture of step (c) to obtain a desired soap composition according to any of the preceding claims from 1 to 10; wherein water is added at any of the steps (a), (b) or (c).

12. Use of amorphous form of aluminosilicate and starch in soap bars comprising moisture in the range of 15 to 45wt% of the soap composition for achieving hardness of at least 3 Kg-F measured at 40°C.

13. Use of 0.1 to 5 wt% of a pH quencher having pKa value between 3.5 to 6.8 or corresponding salt of the acid or combination thereof in a soap composition comprising,a. 18 to 55 wt% of total fatty matter; b. 1.0 to 15.0 wt% of polymeric form of sodium alumino silicate; c. 15 to 45 wt% of water; d. 5 to 45wt% of starch; and wherein the SiCh / AhOs mole ratio of the polymeric form of sodium alumino silicate is equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; and wherein the pH quencher is selected from the group of, polyacrylic acid, salts of polyacrylic acid, dicarboxylic acid, salts of dicarboxylic acid; organic acid, salts of organic acid, and mixtures thereof, to enhance stabilization of the sodium alumino silicate in amorphous form.

14. Use according to claim 13, wherein the pH quencher is selected from the group of organic acid, polyacrylic acid, dicarboxylic acid and salts of these, and mixtures thereof, preferably wherein the pH quencher is selected from the group of citric acid, acetic acid, lactic acid, oxalic acid, tartaric acid, ascorbic acid, maleic acid, maleic anhydrate, acrylic polymer acids, adipic acids, salts thereof and mixtures thereof.

Images