A composition and process for preparing a high moisture soap composition comprising amorphous sodium aluminosilicate

Abstract

The present invention relates to an extruded soap composition. It more particularly relates to a soap composition which comprises alumino silicate to produce soap compositions with high water content that are not only easy to extrude but have the desired hardness. The soap composition comprises: a. 18 to 75 wt% soap; b. 1.0 to 15.0 wt% of sodium alumino silicate; c. 15 to 45 wt% water; and d. 0.1 to 5 wt% of pH quencher having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof; wherein the SiO2 / AI2 03 mole ratio of the sodium alumino silicate equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; and wherein, pH quencher is selected from the group of polyacrylic acid and salts thereof, dicarboxylic acid and salts thereof, organic acid, salts of organic acid, and mixtures thereof.

Description

[0001] A COMPOSITION AND PROCESS FOR PREPARING A HIGH MOISTURE SOAP COMPOSITION COMPRISING AMORPHOUS SODIUM ALUMINOSILICATE

[0002] Field of the invention

[0003] The present invention relates to a soap composition. It more particularly relates to a soap composition 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.

[0008] 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.

[0009] 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.

[0010] 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 alumino silicate gels, were able to develop even better water holding soap compositions by incorporating in them, specific alumino silicate 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.

[0011] WO / 2022 / 180228 (Unilever) discloses a 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.

[0012] Alumino silicate 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] Summary of the invention In a first aspect, the present invention relates to a soap composition comprising, a. 18 to 75 wt% soap; b. 1.0 to 15.0 wt% of sodium alumino silicate; c. 15 to 45 wt% water; and d. 0.1 to 5 wt% of pH quencher acid having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof; wherein the SiCh / AhOs mole ratio of the sodium alumino silicate equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; and wherein, pH quencher is selected from the group of salts of organic acid, polyacrylic acid and dicarboxylic acid or mixtures thereof.

[0017] In a second aspect, the present invention relates to a process to prepare a soap composition according to the first aspect comprising the steps of: a. preparing the sodium alumino silicate in situ in reactor by reacting sodium aluminate with sodium silicate to form amorphous form of sodium alumino silicate, or adding preformed amorphous form of sodium alumino silicate, wherein the SiO2 / AI2C>3 mole ratio of the sodium alumino silicate is equal to or less than 3.0; b. preparing soap in the same reactor by reacting desired amount of fatty acid / oil with alkali to obtain a mixture; c. adding a pH quencher acid having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof to the mixture of step ‘b’; d. passing the mixture of step (c) through a plodder to prepare the soap composition according to the first aspect.

[0018] In a third aspect the present invention provides use of amorphous form of aluminosilicate in soap compositions having moisture in the range of 15 to 45wt% for achieving hardness of at least 3 Kg-F measured at 40°C.

[0019] In a fourth aspect the present invention provides use of soap composition according to the first aspect having a bar hardness of 2.7 to 5.0 Kg when measured at 40°C, using 15 mm penetration value. Detailed description of the invention

[0020] 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.

[0021] Throughout the specification unless otherwise specified, wt% means weight % of the total weight of soap composition of the present invention.

[0022] Various components of the composition are described in greater detail below.

[0023] Soap Composition

[0024] 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.

[0025] The soap composition of the present invention comprises 18 to 75 wt% soap; 1.0 to 15.0 wt% of sodium alumino silicate; water in the range of 15 to 45 wt%; and 0.1 to 5 wt% of pH quencher acid having pKa value between 3.5 to 6.8; wherein the SiCh / AhCh mole ratio of the sodium alumino silicate is equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form.

[0026] 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.

[0027] 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.

[0028] 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 then 8%, preferably less then 4%, more preferably less then 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.

[0029] The soap composition of the invention is capable of stably retaining high amount of water in the range of 15 to 45 wt% as compared to conventional soap composition. Thus, water is preferably at least 18 wt.%, further preferably at least 20 wt.%, still more preferably at least 23 wt.% furthermore preferably at least 25 wt.% but the amount of water in the soap composition is preferably not more than 40 wt.%, still preferably not more than 38 wt.%, most preferably not more than 35 wt.%. In highly preferred aspects, the amount of water in the soap composition ranges from 21 to 40%, more preferably 23 to 40% by weight of the composition. Without wishing to be bound by theory, the inventors believe that aluminosilicate structuring provides a more rigid mortar and harder bricks as compared to without aluminosilicate structuring at comparable moisture level in the soap composition. The rigid mortar is believed to be due to caging of water in the aluminosilicate by hydrogen bonding while harder bricks is believed to be obtained due to efficient interaction between soap and amorphous submicron size particles present in the sodium aluminosilicate gel. 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.

[0030] To resolve all the challenges of high moisture bar processing, the present inventors have been able to make high moisture noodle by incorporating water structuring technology like sodium alumino silicate in soap making stage through plough shear mixer, crutcher etc.

[0031] It was a surprising finding of the present invention that when pH quencher acid was used after the aluminosilicate formation in soap making stage the mass become plastic and no powderiness observed during the stage of noodle conversion.

[0032] Further, it was even surprising that even the form of sodium alumino silicate 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 alumino silicate gel, 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 insitu 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 alumino silicate 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.

[0033] Soap

[0034] When the soap composition of the present invention is for personal washing application it comprises 18 to 75 wt% total amount of soap, preferably 25 to 75 wt%, more preferably 35 to 70 wt% and most preferably 50 to 70 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.% fatty acid soap in the soap composition.

[0035] The term soap means salt of fatty acid. Preferably, the soap is soap of C8 to C24 fatty acids.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] It is preferred that in the soap composition of the present invention the SiCh / AhOs mole ratio of the sodium alumino silicate is in the range of 3:1 to 1 :1. It is preferred that in the soap composition of the present invention the composition comprises 25 to 40 wt% water by weight of the composition.

[0041] It is preferred that in the soap composition of the present invention the soap composition comprises 0.1 to 6 wt% of an electrolyte by weight of the composition.

[0042] It is preferred that in the soap composition of the present invention the electrolyte comprises a compound that is selected from the group of sodium chloride, sodium sulphate, sodium citrate or a mixture thereof.

[0043] It is preferred that in the soap composition of the present invention the electrolyte comprises sodium sulphate in the range of 0.1 to 1.5 wt% of total weight of the composition.

[0044] It is preferred that in the soap composition of the present invention the electrolyte comprises sodium chloride in the range of 0.5 to 1.5 wt% of total weight of the composition.

[0045] It is preferred that in the soap composition of the present invention the iodine value of the soap composition is in the range of 30 to 45 g / lodine per 100 g of the soap.

[0046] It is preferred that in the soap composition of the present invention the composition has a pH in the range from 9 to 13 when measured in a 4% solution with distilled water at 25°C.

[0047] 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.

[0048] The soap composition of the present invention preferably 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.

[0049] 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.

[0050] Sodium alumino silicate

[0051] The composition of the invention comprises selective amount of a sodium alumino silicate 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 alumino silicate is carefully prepared such that the molar ratio of SiCh / AI2O3 is less than 5.0, preferably equal to or less than 3.5, further preferably equal to or less than 3 and most preferably less than 2.8.

[0052] It is preferred that the sodium alumino silicate is prepared in situ, however, it may also be pre-formed and added at the appropriate stage during the process.

[0053] The present inventors with their extensive research experience in the area of alumino silicate gels, have been able to develop high moisture soap compositions by incorporating in them, specific alumino silicate where the SiCh / AI2O3 mole ratio is equal to or less than 3.0. pH Quencher

[0054] 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 preferably selected from the group of salts of organic acid, polyacrylic acid and dicarboxylic acid or mixtures thereof.

[0055] 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. 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.

[0056] 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

[0057] When the acid is a polyacrylic acid, it may be selected from the group comprising and not limited to acrylic polymer acids

[0058] When the acid is a dicarboxylic acid, it may be selected from the group comprising and not limited to adipic acids.

[0059] 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. a. 18 to 75 wt% soap; b. 1.0 to 15.0 wt% of sodium alumino silicate; c. 15 to 45 wt% water; and wherein the SiCh / AhOs mole ratio of the sodium alumino silicate equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form;

[0060] 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. Water

[0061] 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.

[0062] Electrolyte

[0063] 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.

[0064] It is preferred that composition of the invention comprises 0.1 to 6 wt%, preferably 0.5 to 3 wt %, more preferably in the range of 0.5 to 2.5 wt % electrolyte, and most preferably 0.7 to 2.3% by weight of the composition. 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.

[0065] It is most preferred that sodium sulphate and sodium chloride are used as electrolytes for the composition of the present invention.

[0066] It is preferred that sodium sulphate is present in the range of 0.5 to 1.5 wt% of the weight of composition, more preferably 0.7 to 1.3 and most preferably 1 to 1.3 wt%. It is preferred that sodium sulphate is at least 0.5 wt%, more preferably at least 0.7wt%, and most preferably at least 1wt% and it is preferred that it is not more than 3wt%, more preferably not more than 2.5 wt%, further, more preferably not more than 2wt% and most preferably not more than 1 ,5wt% of the total weight of composition of the present invention. It is preferred that when sodium chloride is present in the range of 0.5 to 1.5 wt% of the weight of composition, more preferably 0.7 to 1.3 and most preferably 1.0 to 1.3 wt%. It is preferred that sodium chloride is at least 0.5 wt%, more preferably at least 0.6 wt%, and most preferably at least 0.7 wt% and it is preferred that it is not more than 3wt%, more preferably not more than 2.5 wt%, and further, more preferably not more than 2wt% and most preferably not more than 1.5wt% of the total weight of composition of the present invention.

[0067] Optional ingredients in soap compositions

[0068] 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.

[0069] 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 bars of the invention comprise 0 to 8%, preferably 1 to 7.5% by wt. polyol by weight of the soap bar composition.

[0070] 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 alkali metal salts include sodium sulfate, sodium chloride, sodium acetate, 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, sodium citrate, potassium chloride and especially preferred electrolyte is sodium chloride sodium sulphate, sodium citrate or a combination thereof. For the avoidance of doubt, it is clarified that the electrolyte is a nonsoap material. Electrolyte is preferably included in 0.1 to 6%, more preferably 0.5 to 6%, even more preferably 0.5 to 5%, furthermore preferably 0.5 to 3%, and most preferably 1 to 3% by weight of the composition. It is preferred that the electrolyte is included in the soap composition during the step of saponification to form the soap.

[0071] The various optional ingredients that make up the final soap composition are as described below:

[0072] 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.

[0073] 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.

[0074] 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.

[0075] Preferred inorganic particulate material includes talc 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.

[0076] 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. 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.

[0077] 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.

[0078] 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: ACULYN®, CARBOPOL®, and CARBOPOL® Ultrez grade series.

[0079] 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.

[0080] 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.

[0081] The product can take the form of a water-clear, i.e. transparent soap, in which case it will not contain an opacifier.

[0082] The pH of preferred soaps compositions of the invention is from 8 to 11, more preferably

[0083] 9.5 to 11. 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] The present invention provides use of soap bar composition according to the first aspect to provide soap bars having a bar hardness of 2.7 to 5.0 Kg when measured at 40°C, using 15 mm penetration value.

[0088] The present invention also provides use of amorphous form of aluminosilicate in soap compositions having moisture in the range of 15 to 45wt% for achieving hardness of at least 3 Kg-F measured at 40°C.

[0089] Process

[0090] In a second aspect, the present invention relates to a process to prepare a soap composition of the first aspect comprising the steps of: a. providing soap, b. providing sodium aluminate and providing sodium silicate to form amorphous form of sodium alumino silicate, or adding preformed amorphous form of sodium alumino silicate, c. wherein the SiGh / AhCh mole ratio of the sodium alumino silicate is equal to or less than 3.0; d. adding a pH quencher acid having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof to the mixture of step ‘b’; and e. extruding the mixture to prepare the soap composition according to the first aspect.

[0091] In a preferred aspect a process is provided prepare a soap composition according the first aspect, the process comprising the steps of: a. preparing the sodium alumino silicate in situ in a reactor by reacting sodium aluminate with sodium silicate to form amorphous form of sodium alumino silicate, or adding preformed amorphous form of sodium alumino silicate, wherein the SiCh / AhOs mole ratio of the sodium alumino silicate is equal to or less than 3.0; b. providing a soap or preparing soap in situ in the same reactor; to obtain a mixture; c. adding a pH quencher acid having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof to the mixture of step ‘b’; d. passing the mixture of step (c) through a plodder to prepare the soap composition according to the first aspect.

[0092] It is preferred that step (b) is carried out at 90 to 110°C to obtain a mixture.

[0093] The soap composition may be made into a bar by a process 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.

[0094] The specific process that may be employed using the above described general process for soap composition manufacture comprises one of the following processes.

[0095] 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 alumino silicate in the plough shear mixer or crutcher to mix with the soap so formed in step (a) with said 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.

[0096] 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 in situ in a plough shear mixer or crutcher by reacting the desired amount of sodium aluminate with sodium silicate to form amorphous form of sodium alumino silicate, or adding preformed amorphous form of sodium alumino silicate, wherein the SiCh / AhOs mole ratio of the sodium alumino silicate is equal to or less than 3.0; 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; adding a pH quencher having pKa value between 3.5 to 6.8; and spray drying the mixture or passing it through a triple roll mill; and then passing it though a plodder to prepare the desired soap composition.

[0097] It is preferred that in the process of the present invention the soap is in the range of 18 to 75 wt% of the soap composition.

[0098] It is preferred that in the process of the present invention the sodium alumino silicate is in the range of 2 to 10 wt% of the soap composition.

[0099] It is preferred that in the process of the present invention the soap composition comprises 25 to 40 wt% water of the soap composition.

[0100] 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.

[0101] It is preferred that in the process of the present invention the electrolyte is not a surfactant and is selected from sodium chloride, sodium sulphate, sodium citrate or a mixture thereof.

[0102] It is preferred that in the process of the present invention sodium alumino silicate is formed in situ.

[0103] It is preferred that the soap composition of the present invention is prepared in a plough shear mixer. The sodium alumino silicate and the various methods by which it can be prepared and incorporated in the soap is described below.

[0104] Sodium alumino silicate prepared by reacting sodium silicate and sodium aluminate in aqueous medium. It can be prepared separately in a mixer for incorporation in the soap. Such a process is known as premade or pre-formed route. Alternately it 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. Aluminosilicate 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:

[0105] Method 1 (Pre-made / pre-formed route):

[0106] 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.

[0107] Gel preparation:

[0108] 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.

[0109] Extrusion of soap with the premade aluminosilicate gel:

[0110] The premade 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.

[0111] Method 2 (in-situ route):

[0112] In this route is prepared in the soap making equipment e.g., in the PSM, the crutcher, or PAN mixer). In-situ route in PSM / Crutcher:

[0113] 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 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.

[0114] 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.

[0115] Preparation of the Sodium Alumino Silicate

[0116] The sodium alumino silicate 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).

[0117] Specific example of preparation of ex-situ sodium alumino silicate gel:

[0118] To prepare a sodium alumino silicate of SiO2 / AI2O3 mole ratio 2.05 following sequence of addition and conditions are followed:

[0119] Required quantity (1083gm as 45% aqueous solution) of sodium silicate solution was taken in a 5 litre plastic beaker. Required quantity (2103gm) of process water is added slowly under stirring condition (350 rpm) using an overhead stirrer. Required quantity (1083gm as 45% aqueous solution) of sodium aluminate solution was added slowly into the prediluted aqueous solution of sodium silicate while then stirrer was kept on. The aqueous mixture is allowed to mix for another 5 min at high speed (500 rpm). EXAMPLES

[0120] Example 1- Soap Compositions

[0121] The soap compositions for the examples were prepared in accordance with the present invention.

[0122] 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, Na2SC>4) 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.

[0123] Table 1

[0124] Example 2- Effect of pH Quencher on soap Noodles E1- Composition of the present invention with pH quencher as citric acid+ sodium citrate system.

[0125] E2- Composition of the present invention with pH quencher as adipic acid.

[0126] E3- Composition out of the scope of the present invention without pH quencher. The data of table 2 clearly show that the compositions E1 and E2 having either citric acid and adipic acid respectively are more easy to convert into soap noodles than the one (E3) without such a pH quencher.

[0127] Example 3- Soap Bars prepared in accordance with the soap compositions of the present invention.

[0128] To convert the aluminosilicate containing high moisture noodle into soap bar following steps were followed. The mixing was carried out in sigma mixer following the sequence of addition and mixing time mentioned in Table-3 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- 550mmHg vacuum was maintained.

[0129] 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. Table 3 gives formulation of a soap bar made from E1 and E2 composition having high moisture content of 28 wt% and exhibiting good hardness quality of 2.6-2.8Kgf. A soap bar when attempted to be made by E3 composition resulted in brittle and cracked soap bars. Table 3- Soap Bar

[0130] The hardness of the samples was measured using the procedure described below and the measured values are given in Table 3

[0131] The data in Table 3 above indicates that soap compositions with high moisture content can be prepared as per the present invention (E1 and E2) which extrude well and have high hardness as compared to E3 which cracked during the stamping process.

[0132] Example 3- Performance of soaps with in situ generated sodium alumino silicate with commercially available Zeolite 4A

[0133] In this example the sodium alumino silicate was generate in situ, and compared with the commercially available Zeolite 4A.

[0134] A high moisture noodle (~25%moisture) was prepared by incorporating 3% sodium alumino silicate. In this process after fatty acids neutralization in PSM, required quantity of sodium silicate (45% aqueous solution), sodium aluminate (45% aqueous solution) and process water were added simultaneously at 85-90°C and allowed for 2-3 min of mixing. Then the mass immediately dropped from the mixer and converted into soap noodle. Sodium aluminate to sodium silicate ratio was kept in the range of 30:70 to 40:60. The noodle in next day converted into the shape of bar by adding benefit agents.

[0135] A comparison was made to check the performance difference of the soap bars made from the composition of the present invention, E4 and that made with commercially available Zeolite 4A (Metro Chem Industries) E5 and E6.

[0136] 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 E4 and clear crystalline peaks for composition E5 and E6, thereby confirming that the aluminosilicate is amorphous form, whereas the Zeolite 4A is known to be a crystalline form. 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.

[0137] Table 4- Effect of forms of different forms of sodium alumino silicate 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 (E4) showed no efflorescence even upto 1 year. 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.

[0138] Hardness Testing Protocol

[0139] Principle

[0140] 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 / bil let 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.

[0141] Apparatus and Equipment

[0142] TA-XT Express (Stable Micro Systems)

[0143] 30° conical probe - Part #P / 30c (Stable Micro Systems)

[0144] Sampling Technique

[0145] 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.

[0146] Procedure

[0147] Setting up the TA-XT Express 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.

[0148] Set test method

[0149] Press MENU

[0150] Select TEST SETTINGS (Press 1)

[0151] Select TEST TPE (Press 1)

[0152] Choose option 1 (CYCLE TEST) and press OK

[0153] Press MENU

[0154] Select TEST SETTINGS (Press 1)

[0155] Select PARAMETERS (Press 2)

[0156] Select PRE TEST SPEED (Press 1)

[0157] Type 2 (mm s-1) and press OK

[0158] Select TRIGGER FORCE (Press 2)

[0159] Type 5 (g) and Press OK

[0160] Select TEST SPEED (Press 3)

[0161] Type 1 (mm s-1) and press OK

[0162] Select RETURN SPEED (Press 4)

[0163] Type 10 (mm s-1) and press OK

[0164] Select DISTANCE (Press 5)

[0165] Type 15 (mm) for soap billets or 3 (mm) for soap pastilles and press OK

[0166] Select TIME (Press 6)

[0167] Type 1 (CYCLE)

[0168] Calibration

[0169] Screw the probe onto the probe carrier.

[0170] Press MENU

[0171] Select OPTIONS (Press 3)

[0172] Select CALIBRATE FORCE (Press 1) - the instrument asks for the user to check whether the calibration platform is clear

[0173] Press OK to continue and wait until the instrument is ready.

[0174] Place the 2kg calibration weight onto the calibration platform and press OK Wait until the message “calibration completed” is displayed and remove the weight from the platform.

[0175] Sample Measurements

[0176] Place the billet onto the test platform.

[0177] Place the probe close to the surface of the billet (without touching it) by pressing the UP or DOWN arrows.

[0178] Press RUN

[0179] Take the readings (g or kg) at the target distance (Fin).

[0180] After the run is performed, the probe returns to its original position.

[0181] Remove the sample from the platform and record its temperature.

[0182] Calculation & Expression of Results

[0183] Output

[0184] 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)

[0185] The force reading can be converted to extensional stress, according to the equation given below.

[0186] The equation to convert the TX-XT readout to extensional stress is where: o = extensional stress

[0187] C = "constraint factor" (1.5 for 309cone)

[0188] Gc= acceleration of gravity

[0189] A = projected area of cone = d = penetration depth

[0190] 0 = cone angle

[0191] For a 30° cone at 15 mm penetration, Equation 2 becomes ct (Pa) = RT(g) x 128.8 This stress is equivalent to the static yield stress as measured by penetrometer.

[0192] The extension rate is: where E = extension rate (s-1)

[0193] V = cone velocity

[0194] For a 30° cone moving at 1mm / s, E = 0.249 s-1

[0195] Temperature Correction

[0196] 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:

[0197] R40= RT x exp[a(T-40)] where R40 = reading at the reference temperature (40°C)

[0198] RT = reading at the temperature T a = coefficient for temperature correction

[0199] T = temperature at which the sample was analyzed.

[0200] The correction can be applied to the extensional stress.

[0201] Raw and Processed Data

[0202] The result is the temperature-corrected force or stress, but it is advisable to record the instrument reading and the sample temperature also.

[0203] A hardness value of at least 1.2 kg (measured at 40°C), preferably at least 2.7 kg is acceptable.

Claims

Claims1. A soap composition comprising, a. 18 to 75 wt% soap; b. 1.0 to 15.0 wt% of sodium alumino silicate; c. 15 to 45 wt% water; and d. 0.1 to 5 wt% of pH quencher having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof; wherein the SiCh / AhCh mole ratio of the sodium alumino silicate equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; and wherein, pH quencher is selected from the group of polyacrylic acid and salts thereof, dicarboxylic acid and salts thereof, organic acid, salts of organic acid, and mixtures thereof.

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

3. A soap composition according to anyone of the preceding claims 1 or 2, wherein the composition comprises 25 to 40 wt% water by weight of the composition.

4. A soap composition according to anyone of the preceding claims from 1 to 3, wherein the soap composition comprises 0.1 to 6 wt% of an electrolyte by weight of the composition.

5. A soap composition according to claim 4, wherein the electrolyte comprises a compound that is selected from the group of sodium chloride, sodium sulphate, sodium citrate or a mixture thereof.

6. A soap composition according to claims 4 or 5, wherein the electrolyte comprises sodium sulphate in the range of 0.1 to 1.5 wt% of total weight of the composition.

7. A soap composition according to claims 4 or 5, wherein the electrolyte comprises sodium chloride in the range of 0.5 to 1.5 wt% of total weight of the composition.

8. A soap composition according to anyone of the preceding claims from 1 to 7, wherein the iodine value of the soap composition is in the range of 30 to 45 g / lodine per 100 g of the soap.

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

10. A process to prepare a soap composition according to any one of the preceding claims from 1 to 9, the process comprising the steps of: a. preparing the sodium alumino silicate in reactor by reacting sodium aluminate with sodium silicate to form amorphous form of sodium alumino silicate, or adding preformed amorphous form of sodium alumino silicate, wherein the SiO2 / AI2C>3 mole ratio of the sodium alumino silicate is equal to or less than 3.0; b. providing a soap or preparing soap in the same reactor to obtain a mixture; c. adding a pH quencher having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof to the mixture of step ‘b’; d. passing the mixture of step (c) through a plodder to prepare the soap composition according to claims 1 to 9.

11. A process to prepare a soap composition according to claim 10, wherein the step (b) is carried out at 90 to 110 °C to obtain the mixture.

12. Use of soap composition according to claims 1 to 9 to provide soap bars having a having moisture in the range of 15 to 45wt% for achieving hardness of at least 2.7 Kg-F measured at 40°C.

13. Use of amorphous form of aluminosilicate for manufacturing soap bars according to claims 1 to 9 having a bar hardness of 2.7 to 5.0 Kg when measured at 40°C, using 15 mm penetration value.

14. Use of 0.1 to 5 wt% of pH quencher having pKa value between 3.5 to 6.8 or corresponding salt or combination thereof in a soap composition comprising, a. 18 to 75 wt% soap; b. 1.0 to 15.0 wt% of sodium alumino silicate; c. 15 to 45 wt% water; and wherein the SiCh / AhOs mole ratio of the sodium alumino silicate equal to or less than 3.0; and wherein the sodium alumino silicate is in amorphous form; to enhance stabilization of the sodium alumino silicate in amorphous form.

15. Use according to claim 14, 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.

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