Soap composition comprising hydrogel

Abstract

A soap composition comprising: (i) a saponified fatty material made from a fat blend comprising lauric fatty acid and saturated and unsaturated non-lauric fatty acids; and (ii) a hydrogel which is non-thermoreversible at 70 to 140° C. Also disclosed are a soap bar comprising the soap composition and a method for preparing the soap composition.

Description

Technical Field

[0001] The present invention belongs to the field of soap products, in particular soap noodles and soap bars made therefrom. Background Art

[0002] Bars of soap bars are usually made from soap slivers, which usually have 40% to 80% by weight or more total fatty matter (TFM), 10 to 35% by weight water (moisture) and additives such as fillers, salts, other surfactants and fragrances. These bars are mainly produced by mixing soap slivers with other ingredients, followed by grinding, extrusion and stamping steps.

[0003] Soap bars are generally prepared from oils or fats or blends by methods well known in the art. One method is direct saponification of the oil / fat, wherein the oil / fat is reacted with an alkali (usually sodium hydroxide) to form glycerol and a soap base (which contains an alkali metal salt of a fatty acid, such as a sodium salt of a fatty acid, which is also a sodium salt of a carboxylic acid). A soap base is a material containing an alkali metal salt of a fatty acid. Thus, the material after the removal of glycerol (if glycerol is to be removed) and to be further processed is an example of a soap base. Another method involves neutralizing the fatty acid with an alkali (e.g., sodium hydroxide) to form a soap base. During the soap preparation process, the soap base may be dried and pressed into thin bars or pieces. As used herein, the term "soap bars" refers to particles or pieces of soap (whether they are particles, pieces, small pieces or other shapes). Soap bars are generally the result of drying and extruding the raw soap into a unit form, so that the soap units or pieces can be further processed into finished soap bars by mixing with additives as known to those skilled in the art of soap preparation.

[0004] In the saponification process, various fats (e.g., tallow, palm and / or coconut or PKO oil blends) are saponified in the presence of a base (usually sodium hydroxide) to produce alkaline salts of fatty acids (from the fatty acid chains that form the glycerides) and glycerol. The glycerol is then typically extracted with brine to produce a dilute fatty acid soap solution containing soap (the soap formed after saponification and before extrusion into the final bar is often referred to as soap "slivers") and an aqueous phase (e.g., 70% soap and 30% aqueous phase).

[0005] The chain length of the soap depends on the fat or oil raw material (which is usually a blend). For the purposes of this specification, "oil" and "fat" are used interchangeably unless the context requires otherwise. Longer chain fatty acid soaps (e.g., C 16 Palmitic acid or C 18 Stearic acid) is commonly obtained from tallow and palm oil, shorter chain soaps (e.g., C 12 Lauric acid) is commonly available from, for example, coconut oil or palm kernel oil. The fatty acid soaps produced may also be saturated or unsaturated (e.g., oleic acid).

[0006] Typically, longer chain fatty acid soaps (e.g., C14 To C 22 Soaps), especially longer, saturated soaps, are insoluble and do not produce sufficient foam when used, but they can make the foam finer and more stable. In contrast, shorter chain soaps (e.g., C8-C 12 ) and unsaturated soaps (e.g., oleic or linoleic soaps) lather very quickly. However, longer chain soaps (usually saturated, although they can also contain some level of unsaturation, such as oleic acid) are ideal for maintaining structure and not dissolving as easily. Unsaturated soaps (e.g., oleic acid) are soluble and lather quickly, like short chain soaps, but form a denser, more creamy foam, like longer chain soaps.

[0007] Typically, bars formed by extrusion rather than cast melt processes are expected to be sufficiently hard (not too viscous to clog the machine or too inelastic to slow production rates and cause cracking) so that the soap can be extruded at a high enough rate. Typically, oils or fatty acids with an iodine value (IV) of 30-43, preferably 38-42, are used for this purpose.

[0008] Hardness depends on the iodine value of the oil being saponified. Oils and fats with a high average unsaturation are considered to have a high iodine value; oils and fats with a low average unsaturation are said to have a low iodine value. Typically, soap bars made from oils with a higher iodine value (more unsaturated) are softer, while soap bars made from oils with a lower IV value (more saturated) are harder. The iodine value is a well-known standard for measuring unsaturation, and the measurement of IV is well known and understood. For example, a well-known method is to use gas chromatography. Using this method, methyl esters of the fatty acid chains in the oil are formed and analyzed by gas chromatography.

[0009] An increase in the IV of the oil, and correspondingly the IV of the soap, increases their water solubility, so the soap bar tends to become softer. In addition, an increase in IV tends to affect the stability of the composition due to an increase in peroxide value. However, when formulation scientists want to prepare soap bars from high IV oils and / or fatty acids, they tend to rely on electrolytes as antioxidants or certain thickeners to increase the hardness of the soap bar.

[0010] US2019284513A1 (Unilever) discloses soap bars made predominantly (>50%) of one or more oils of defined IV, containing an amount of potassium soap. The bars are easier to extrude and do not crack as much while exhibiting lower abrasive and mush values. By specifically saponifying the oil so that 5% to 15% potassium soap elongated bars are formed (as a percentage of the total soap composition), a starting oil with IV 37 can be used.

[0011] EP0537964A1 (Unilever, 1993) discloses a soap bar containing 90 to 50% fatty acid soap obtained from tallow (non-lauric fat) and 10 to 50% fatty acid soap obtained from coconut (lauric fat). The soap bar contains at least 25% by weight of lauric soap, the balance of non-lauric soap having an iodine value (IV) of less than 45 and at least 5% by weight of mild active substances.

[0012] US2019016994A1 (Univ of Alabama) discloses soap flakes containing a polymer matrix comprising a first polymer, a polysaccharide (uniformly distributed in the polymer matrix) and a fatty acid. The soap flakes are user-friendly.

[0013] WO9928429A1 (Bush Boake Allen) discloses soap bars containing a gel prepared from a hydrocarbon and a polymeric gelling agent.

[0014] WO2011080101A1 (Unilever) discloses a low TFM soap bar having a continuous phase substantially free of water-soluble builders. The phase contains 20% to 50% TFM, of which the unsaturated fatty acid soap is less than 39% by weight of the fatty acid soap. The bar has a structuring system comprising 10 to 45% by weight of a polysaccharide structurant selected from the group consisting of starch, cellulose and 6 to 30% by weight of a polyol selected from the group consisting of glycerol and sorbitol. The bar contains 0.5 to less than 3% of an anti-cracking agent, which is a carboxymethylcellulose, a polyacrylate polymer, and 10 to 20% water.

[0015] US2011077186A1 (J&J) discloses a low TFM soap bar containing a solid soap base and hydrogel phase particles dispersed therein to act as a filler and reduce TFM, and addresses the need for a low TFM soap bar with an increased amount of water or filler. The bar contains a hydrogel filler, which is a coreless composite material, preferably comprising a polyol or powder. The constituent materials remain separated and differentiated at a macroscopic level within the final structure, and this hydrogel phase in the soap structure leads to new soaps and new soap making processes. Hydrogels are referred to as gels that contain water but are insoluble in water. For example, when water is placed on top of the hydrogel, the hydrogel and water clearly separate into two phases. The hydrogel is prepared externally in a premixer and then mixed with the soap elongated bar.

[0016] KR1020090010344A (LG Household, 2009) discloses a soap composition containing 0.5 to 60% by weight of a hydrated polysaccharide gel (alginate, pectin, gellan gum, carrageenan), 5 to 80% by weight of water, and 1 to 20% by weight of a fatty acid soap. The pre-prepared gel is mixed with the fatty acid during neutralization.

[0017] It is an object of the present invention to prepare soap bars using high iodine value oils or fatty acids while still maintaining at least one of the important properties of hardness, mush, wear rate or cracking.

[0018] Unexpectedly, we have determined that including a hydrogel that is non-thermoreversible at 70 to 140°C in a soap composition (such as bars and strips) comprising a saponified fatty material made from a fat blend having an iodine value of 44 to 58 g / iodine per 100 g improves some properties of the soap composition. Summary of the invention

[0019] According to a first aspect, there is disclosed a soap composition comprising:

[0020] i) a saponified fatty material made from a fat blend comprising lauric fatty acid and saturated and unsaturated non-lauric fatty acids; and

[0021] ii) a hydrogel which is thermoreversible at 70 to 140°C; preferably, wherein the hydrogel does not become a flowable liquid again when heated beyond an elevated temperature in the range of 70 to 140°C.

[0022] The iodine value of the saponified fatty substance is 44-58 g / iodine per 100 g of the saponified fatty substance.

[0023] According to a second aspect, a method for preparing a soap composition is disclosed, comprising the steps of:

[0024] i) heating a fat blend comprising lauric fatty acids and saturated and unsaturated non-lauric fatty acids to 60 to 80° C. in a blending tank, wherein the fat blend has an iodine value of 44 to 58 g / iodine per 100 g;

[0025] ii) adding at least one reactant from the first group of reactants consisting of a water-soluble polycarboxylic acid, a water-soluble salt of such an acid, calcium chloride, a borate, or OHC(CH2)nCHO, wherein n=2 to 6, while maintaining the temperature at 60°C to 80°C;

[0026] iii) adding alkali to saponify the fat blend; and

[0027] iv) adding at least one of a second group of reactants consisting of a polyol, an alkaline silicate or a cellulose derivative for in situ production of the hydrogel by chemical cross-linking of the functional groups of the first group of reactants with the corresponding reactive functional groups of the second group of reactants, wherein the temperature is maintained in the range of 90 to 110°C, and wherein steps (ii) and (iv) are interchangeable.

[0028] Further disclosed is a method of preparing a soap composition comprising the steps of:

[0029] i) heating a fat blend comprising lauric fatty acids and saturated and unsaturated non-lauric fatty acids to 60 to 80° C. in a blending tank, wherein the fat blend has an iodine value of 44 to 58 g / iodine per 100 g;

[0030] ii) adding alkali to saponify the fat blend; and

[0031] iii) adding to the saponified material of step (ii) a hydrogel prepared by mixing at least one reactant from a first group of reactants consisting of a water-soluble polycarboxylic acid, a water-soluble salt of such an acid, calcium chloride, a borate or OHC(CH2)nCHO, wherein n=2 to 6, and at least one reactant from a second group of reactants consisting of a polyol, an alkaline silicate or a cellulose derivative, wherein after the addition of the hydrogel, the temperature is maintained in the range of 90 to 110°C.

[0032] The term "non-thermoreversible" when applied to hydrogels refers to hydrogels that are non-flowable in the range of 70 to 140°C, and wherein the hydrogel does not become a flowable liquid again when heated beyond this elevated temperature.

[0033] The term "hydrogel solution" refers to a solution or dispersion or colloidal solution in which more than 90% of the hydrogel has dissolved or is in colloidal form.

[0034] As used herein, the term "comprising" encompasses the terms "consisting essentially of" and "consisting of". Where the term "comprising" is used, the steps or options listed do not need to be exhaustive. Unless otherwise specified, numerical ranges expressed in the form of "from x to y" are to be understood to include x and y. When specifying any value or amount range, any particular upper limit value or amount may be associated with any particular lower limit value or amount. Except in the examples and comparative experiments, or where otherwise explicitly indicated, all figures are to be understood to be modified by the word "about". Unless otherwise specified, all percentages and ratios contained herein are calculated by weight. Unless otherwise specified, the indefinite article "a" or "an" and its corresponding definite article "the" used herein refer to at least one or one or more. The various features of the present invention mentioned in the above individual sections are appropriately applicable to other sections with necessary modifications. Therefore, the features specified in one section may be appropriately combined with the features specified in other sections. Any section headings are added only for convenience and are not intended to limit the present disclosure in any way. The present invention is not limited to the embodiments shown in the accompanying drawings. It should therefore be understood that when features mentioned in the claims are followed by reference signs, such reference signs are merely intended to improve the intelligibility of the claims and do not limit the scope of the claims in any way.

[0035] The various components of the composition are described in more detail below. DETAILED DESCRIPTION

[0036] The composition of the present invention comprises:

[0037] i) a saponified fatty material made from a fat blend comprising lauric fatty acid and saturated and unsaturated non-lauric fatty acids; and

[0038] ii) Hydrogels that are thermoreversible between 70 and 140 °C.

[0039] The iodine value of the saponified fatty substance is 44-58 g / iodine per 100 g of the saponified fatty substance.

[0040] The iodine value is an indication of unsaturation, and there are known methods for measuring IV. One method is gas chromatography. In this method, methyl esters of fatty acids are formed and analyzed by chromatographic techniques. In addition, there are wet chemical analysis methods.

[0041] The iodine value of the fat blend may be measured prior to saponification. Additionally, the iodine value of the soap (saponified oil or fatty acid) present in the finished product (such as a soap bar or soap strips) may be determined.

[0042] It is preferred that the iodine value of the saponified fatty substance is 46 to 56 g / iodine per 100 g of saponified fatty substance, more preferably 48 to 52 g / iodine per 100 g.

[0043] The expression known as total fatty matter is very widely used in the soap and detergent art. The term abbreviated "TFM" is used to denote the weight percent of fatty acid and triglyceride residues present in a soap composition, without taking into account accompanying cations. For a soap having 18 carbon atoms, the accompanying sodium cation typically constitutes about 8% by weight. Other cations, such as zinc, potassium, magnesium, alkylammonium and aluminum, may be used as desired.

[0044] It is preferred that the compositions of the present invention comprise from 40 to 80 wt% TFM, more preferably from 40 to 72 wt% TFM.

[0045] The term soap refers to a salt of a fatty acid, wherein the accompanying cation may be an alkali metal, alkaline earth metal or ammonium ion, preferably an alkali metal. Preferably, the cation is sodium or potassium. The soap may be saturated or unsaturated, depending on the nature of the corresponding fatty acid and / or oil used for the saponification.

[0046] It is preferred that the fat blend comprises 10 to 20 parts by weight of lauric fatty acids, 35 to 50 parts by weight of saturated non-lauric fatty acids and 20 to 45 parts by weight of unsaturated non-lauric fatty acids, wherein the sum of all fatty acids is 100 parts by weight.

[0047] Lauric fatty acids are fatty acids derived from, for example, coconut oil or palm kernel oil and contain C 12 The fatty acids are lauric acid, but may contain small amounts (up to 5% by weight) of shorter or longer chain fatty acids, such as C 10 To C 14 Preferably, the lauric fatty acid is derived from coconut oil or palm kernel oil.

[0048] Saturated non-lauric fatty acids are those with a content higher than C 14 The saturated fatty acids are preferably saturated fatty acids of carbon chain length. Preferably, the saturated non-lauric fatty acids include at least one of palmitic acid, myristic acid or stearic acid. Such fatty acids may contain up to 2 to 3% by weight of other longer or shorter chain fatty acids, such as C 20 .

[0049] Unsaturated non-lauric fatty acids are unsaturated fatty acids with a content higher than C 12 Preferably, the unsaturated non-lauric fatty acids comprise one or more of oleic acid, linoleic acid, palmitoleic acid or linolenic acid. Such fatty acids may contain up to 2 to 3% by weight of other longer or shorter chain fatty acids, such as C 20or C8. Preferably, the unsaturated non-lauric fatty acids are obtained from at least one of tallow, lard, soybean oil, sunflower oil, rice bran oil, linseed oil, olive oil, rapeseed oil, peanut oil or fish oil. A variety of other alternative sources may be used, such as bioengineered oils.

[0050] Commercially available blends that may be used with appropriate modifications or additional oils / fats include 80 / 20, 85 / 15 blends, where the larger number represents the parts by weight of non-lauric fatty acids and the smaller number represents the parts by weight of lauric fatty acids.

[0051] The composition according to the invention comprises from 0.2 to 5% by weight of hydrogel, more preferably from 0.4 to 2.5% by weight of hydrogel. Hydrogels are crosslinked networks of hydrophilic, water-soluble polymers. They have a tendency to absorb large amounts of water and swell.

[0052] Preferably, the hydrogel is a cross-linked reaction product of at least one of the first set of reactants and at least one of the second set of reactants:

[0053] (a) wherein the first set of reactants consists of a water-soluble polycarboxylic acid, a water-soluble salt of such an acid, calcium chloride, a borate, and OHC(CH2)nCHO (wherein n=2 to 6); and

[0054] (b) The second group of reactants consists of a polyol, an alkaline silicate and a cellulose derivative.

[0055] When the reactant from the first group is a water-soluble polycarboxylic acid or a water-soluble salt of such an acid, the acid is preferably citric acid, glutaric acid or tartaric acid. When the reactant is a salt, it is preferably a sodium or potassium salt.

[0056] When the reactant from the first group is a borate, it is preferably sodium tetraborate decahydrate, calcium borate, calcium magnesium borate, sodium borate, boric acid or mixtures thereof.

[0057] Alternatively, when the reactant from the first group is a compound of formula OHC(CH2)nCHO (wherein n=2 to 6), preferably n=3 and the compound is glutaraldehyde.

[0058] Without being bound by theory, it is believed that when reactants from the above two groups are allowed to react during the soap making process, a non-thermoreversible hydrogel is generated in situ by chemical crosslinking of functional groups of reactants from the first group of reactants with functional groups of reactants from the second group of reactants.

[0059] The second set of reactants consists of a polyol, an alkaline silicate and a cellulose derivative.

[0060] Polyols are used herein to refer to compounds having multiple hydroxyl groups (at least two, preferably at least three) which are highly water-soluble, preferably readily soluble, in water. Many types of polyols are available, such as relatively low molecular weight short-chain polyols (such as glycerol and propylene glycol); sugars (such as sorbitol, mannitol, sucrose and glucose); modified carbohydrates (such as hydrolyzed starch, dextrin and maltodextrin), and polymerized synthetic polyols (such as polyalkylene glycols, such as polyethylene glycol (PEG) and polypropylene glycol (PPG)). Preferred polyols are relatively low molecular weight compounds that are liquid or easily form stable highly concentrated aqueous solutions, such as greater than 50% by weight, preferably 70% by weight or greater in water. These include low molecular weight polyols and sugars. When the reactant is a polyol, it is preferably polyethylene glycol, propylene glycol, glycerol or sorbitol.

[0061] When the reactant from the second group of reactants is a cellulose derivative, it is preferably microcrystalline cellulose (e.g. GP 1030), or a hydroxyalkyl alkyl cellulose ether. Alternatively, the preferred cellulose derivative is a cellulose ether selected from an alkyl cellulose, a hydroxyalkyl cellulose and a carboxyalkyl cellulose. More preferably it is a hydroxyalkyl cellulose or a carboxyalkyl cellulose. Preferred hydroxyalkyl celluloses include hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and ethyl hydroxyethyl cellulose. Preferred carboxyalkyl celluloses include carboxymethyl cellulose. Particularly preferred carboxymethyl cellulose is sodium carboxymethyl cellulose.

[0062] Sodium carboxymethylcellulose (SCMC) is a derivative of cellulose formed by the reaction of cellulose with alkali and chloroacetic acid.Carboxymethylcellulose (CMC) is a biodegradable derivative of cellulose that is considered ideal for preparing hydrogels due to its high swelling capacity.

[0063] Alternatively, the reactant from the second group of reactants is an alkaline silicate. It is preferably in the form of a powder, solution or slurry. Preferably, the alkaline silicate is sodium silicate. Preferably, the molar ratio of SiO2:Na2O in the alkaline silicate ranges from 1 to 4, more preferably from 1.5 to 2.5, most preferably 2.

[0064] Without being bound by theory, a mechanism for the cross-linking reaction leading to hydrogel formation is provided below using citric acid and sodium carboxymethylcellulose as exemplary reactants in each of the two groups.

[0065] The hydrogel is formed by crosslinking by means of esterification. At sufficiently high temperatures, citric acid forms cyclic anhydrides and esterifies hydroxyl groups present on adjacent polymer chains. This results in crosslink formation that usually occurs in the dry state and requires elevated temperatures. The esterification of the -OH functional groups of the polysaccharide with the cyclic anhydride intermediate results in the hydrogel.

[0066] It is particularly preferred that when the reactant from the first group of reactants is a water-soluble polycarboxylic acid or a water-soluble salt of such an acid, the corresponding reactant from the second group of reactants is a cellulose derivative. In particular, it is preferred that when the water-soluble polycarboxylic acid is citric acid and the water-soluble salt of such an acid is sodium citrate, the cellulose derivative is SCMC.

[0067] Alternatively, preferably, when the reactant from the first group is a water-soluble polycarboxylic acid or a water-soluble salt of such an acid, the corresponding reactant from the second group of reactants is an alkaline silicate. In particular, it is preferred that the water-soluble polycarboxylic acid is citric acid, the water-soluble salt of such an acid is sodium citrate, and the alkaline silicate is sodium silicate.

[0068] Further, optionally, it is preferred that when the reactant from the first group of reactants is OHC(CH2)nCHO (wherein n=2 to 6), the corresponding reactant from the second group of reactants is a polyol. In particular, it is preferred that OHC(CH2)nCHO is glutaraldehyde and the polyol is glycerol or sorbitol or polyethylene glycol.

[0069] Form and format

[0070] The soap composition of the present invention may be in any physical form. It is preferably in the form of a bar, sheet, flake, chip or powder, more preferably a bar.

[0071] The term "slivers" is used to refer to generally cylindrical particles prepared by extruding and cutting or breaking up long strands, usually containing soap as the main ingredient.

[0072] Soap-based slivers are usually prepared by mixing dried soap chips with colorants and other minor ingredients, homogenizing by processing in a grinder or refiner, and then extruding through a perforated plate with fine holes. They are usually extruded continuously and then fully weathered to break down into blocks with a length of 3-15 mm. A series of rotating blades can be adapted to the face of the plate to automatically cut the extruded slivers into suitable lengths, but these tend to cause a certain amount of bunching to occur. The degree of bunching depends on the geometry of the cutting blades and the holes, and is also greatly affected by the plasticity and viscosity of the slivers themselves. Even in the case of not using rotating blades, the quality of the slivers depends on the physical properties of the extruded soap. Ideally, the soap should have enough plasticity to satisfactorily extrude through the holes in the perforated plate, but not too soft and too sticky so that they cluster together after extrusion. They should also be hard and brittle enough to break down into the required length range.

[0073] While soap strips can be used for washing and cleaning purposes, in practice such strips are used as input or raw material for making soap bars or soap tablets which are sold in shops and supermarkets and used by consumers as personal washing compositions.

[0074] Thus, according to another aspect of the invention there is disclosed a soap bar comprising the soap composition of the first aspect of the invention. The soap bar may be of any shape and size but is preferably rectangular with rounded edges and of a size allowing it to be held comfortably in one hand.

[0075] Other Ingredients

[0076] In addition to the saponified fatty material and the hydrogel, the soap compositions of the present invention, such as the slim bars, and especially the soap bars, preferably contain one or more of the following other ingredients. The choice of ingredients and their amounts is largely up to the formulation scientist and the purpose for which the slim bars or bars are prepared.

[0077] Non-soap surfactants

[0078] The composition of the present invention preferably comprises a non-soap surfactant as a co-surfactant and is selected from anionic, nonionic, zwitterionic, amphoteric or cationic surfactants. Preferably, the composition comprises 0.1 to 15% by weight of the non-soap surfactant. More preferably, the composition comprises 2 to 10% by weight of the non-soap surfactant, most preferably 3 to 6% by weight.

[0079] Suitable anionic surfactants include water-soluble salts of organic sulfur reaction products having in their molecular structure an alkyl group containing from 8 to 22 carbon atoms and a group selected from sulfonic acid or sulfate groups, and mixtures thereof.

[0080] Examples of suitable anionic surfactants are sodium and potassium alcohol sulfates, especially those obtained by sulfation of higher alcohols produced by reduction of glycerides of tallow or coconut oil; sodium and potassium alkylbenzene sulfonates, for example those in which the alkyl group contains from 9 to 15 carbon atoms; sodium alkyl glyceryl ether sulfates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut fatty acid monoglyceride sulfate; sodium and potassium sulfates of sulfates of reaction products of 1 mol of higher fatty alcohols with 1 to 6 mol of ethylene oxide; sodium and potassium sulfates of alkylphenol ethylene oxide ether sulfates having 1 to 8 units of ethylene oxide and in which the alkyl group contains from 4 to 14 carbon atoms; reaction products of fatty acids esterified with isethionates and neutralized with sodium hydroxide, wherein, for example, the fatty acids are derived from coconut oil, and mixtures thereof.

[0081] 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 alkylbenzene sulfonic acids and mixtures with olefin sulfonates and higher alkyl sulfates, and higher fatty acid monoglyceride sulfates. Suitable nonionic surfactants can be broadly described as compounds produced by the condensation of alkylene oxides, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature. The hydrophilicity or length of the polyoxyalkylene group which is condensed with any particular hydrophobic group can be readily adjusted to produce a water-soluble compound having the desired degree of balance between the hydrophilic and hydrophobic elements.

[0082] Specific examples include condensation products of aliphatic alcohols having 8 to 22 carbon atoms in a straight or branched configuration with ethylene oxide, such as coconut oil ethylene oxide condensates having 2 to 15 moles of ethylene oxide per mole of coconut oil alcohol; condensations of alkylphenols having 6 to 12 carbon atoms in the alkyl group with 5 to 25 moles of ethylene oxide per mole of alkylphenol; condensations of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensations containing 40 to 80% by weight of polyoxyethylene groups and having a molecular weight of 5,000 to 11,000; tertiary amine oxides of the structure R3NO in which one radical R is 8 to 12 carbon atoms; 18 carbon atoms alkyl group, the other R group is methyl, ethyl or hydroxyethyl, such as dimethyl dodecylamine oxide; tertiary phosphine oxide of structure R3PO, in which one group R is an alkyl group of 10 to 18 carbon atoms, and the other R groups are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, such as dimethyl dodecylphosphine oxide; and dialkyl sulfoxide of structure R2SO, in which the group R is an alkyl group of 10 to 18 carbon atoms, and the other R group is methyl or ethyl, such as methyl tetradecyl sulfoxide; fatty acid alkyl alcohol amide; ethylene oxide condensation product of fatty acid alkyl alcohol amide and alkyl mercaptan.

[0083] Suitable cationic surfactants that may be incorporated are alkyl-substituted quaternary ammonium halide salts (e.g., di(hydrogenated tallow) dimethyl ammonium chloride, cetyltrimethylammonium bromide, benzalkonium chloride and dodecylmethylpolyoxyethylene ammonium chloride), as well as amine salts and imidazoline salts (e.g., primary, secondary and tertiary amine hydrochlorides and imidazoline hydrochlorides).

[0084] Suitable amphoteric surfactants are derivatives of secondary and tertiary aliphatic amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic group substituted with an anionic water-solubilizing group, for example sodium 3-dodecylaminopropionate, sodium 3-dodecylaminopropane sulfonate and sodium N-2-hydroxydodecyl-N-methyltaurate.

[0085] Suitable zwitterionic surfactants are derivatives of aliphatic quaternary ammonium, sulfonium and phosphonium compounds having an aliphatic group having 8 to 18 carbon atoms and an aliphatic group substituted with an anionic water-solubilizing group, for example 3-(NN-dimethyl-N-hexadecylammonium)propane-1-sulfobetaine, 3-(dodecylmethylsulfonium)propane-1-sulfobetaine and 3-(hexadecylmethylphosphonium)ethanesulfobetaine.

[0086] Further examples of suitable detergent-active compounds are the compounds customarily used as surface-active agents given in the well-known textbooks “Surface Active Agents”, Volume I (Schwartz and Perry) and “Surface Active Agents and Detergents”, Volume II (Schwartz, Perry and Berch).

[0087] Electrolytes

[0088] Including small amounts of electrolytes (other than soap) can affect the ratio of liquid to solid phases. Increasing the electrolyte content reduces the solubility of the soap, thereby increasing the amount of solid phase, while reducing the electrolyte content makes the bar softer.

[0089] Preferably, the composition of the present invention comprises 1 to 20% by weight, more preferably 2 to 15% by weight, most preferably 3 to 10% by weight of electrolyte based on the weight of the composition. Preferred electrolytes include sodium sulfate, sodium chloride, sodium citrate, potassium chloride, potassium sulfate, sodium carbonate and other alkaline earth metal mono- or di- or tri-salts, more preferably sodium chloride, sodium sulfate, potassium chloride, particularly preferred electrolytes are sodium chloride and sodium sulfate, and combinations thereof. For the avoidance of doubt, it is hereby clarified that the electrolyte is a non-soap material.

[0090] Sunscreen

[0091] Sunscreens may optionally be present in the composition. When sunscreens are present, the cleansing bar is typically not transparent, i.e., "opaque". Examples of sunscreens include titanium dioxide, zinc oxide, and the like. When an opaque rather than transparent soap composition is desired, a particularly preferred sunscreen that may be used is ethylene glycol monostearate or ethylene glycol distearate, for example in the form of a 20% solution in sodium lauryl ether sulfate. An optional sunscreen is zinc stearate.

[0092] Beneficial Agents

[0093] Preferably, the soap composition of the present invention comprises one or more previously undisclosed benefit agents. Preferably, the benefit agent is an emollient, sunscreen, anti-aging compound or moisturizer and humectant. These agents may be added at appropriate steps during processing. Some benefit agents may be introduced as macro domains.

[0094] Examples of moisturizers and humectants include cetyl alcohol, ethoxylated castor oil, paraffin oil, lanolin and its derivatives. Silicone compounds, such as silicone surfactants, such as 3225C (Dow Corning), and / or silicone emollients, silicone oil ( from Dow Corning). Further examples include glycerol, oatmeal, petrolatum, aquaporin manipulation and hydroxyethyl urea.

[0095] Sunscreen agents such as 4-tert-butyl-4'-methoxydibenzoylmethane (trade name 1789 from Givaudan) or 2-ethylhexylmethoxycinnamic acid (available under the trade name MCX available from Givaudan) or other UV-A and UV-B sunscreens. Further examples include (Diethylhexyl naphthoate), Ethylhexyl salicylate, (S&M), and

[0096] Lipids such as cholesterol, ceramides and pseudoceramides and exfoliating particles such as polyethylene beads, walnut shells, apricot kernels, petals and seeds may also be present. Structuring agents such as maltodextrin or starch may be used to give structure to the bar.

[0097] The composition may also optionally contain other ingredients conventionally used in soaps, such as foam boosters, colorants and sunscreens and skin tone agents, such as hexylresorcinol, soy extract (Bowman Birk inhibitor), octadecene dioic acid ( DC), niacinamide, Acetyl Glucosamine, Pitera Extract, and (Calcium pantothenate). In addition, the composition of the present invention may include anti-aging ingredients such as retinol, hyaluronic acid, collagen, CoQ10 (ubiquinone), retinyl propionate, peptides, retinyl palmitate, jasmonic acid derivatives and

[0098] Other auxiliary materials may include fungicides and preservatives. These ingredients are usually present in an amount less than 2% by weight, usually less than 0.5% by weight, and may include silver salts and silver compounds, thymol, terpineol and its analogs, ZPTO, chloroxylenol, PCMX, triclosan and triclocarban.

[0099] The soap composition may include a structurant. These may include water insoluble particulate materials. The structurants may comprise 0 to 25% by weight, either alone or in combination. Preferred inorganic particulate materials include talc and calcium carbonate. Talc is a magnesium silicate mineral material having a sheet silicate structure, consisting of the chemical formula Mg3Si4(O) 10 Talc has a plate-like morphology and is essentially oleophilic / hydrophobic.

[0100] Examples of other optional insoluble inorganic particulate materials include zeolite aluminates, silicates, phosphates, insoluble sulfates, clays (eg, kaolin, china clay), titanium oxide, zinc oxide, and combinations thereof.

[0101] The composition of the present invention may further comprise an anti-cracking agent, such as an acrylate polymer.

[0102] As used herein, the term "slip modifier" refers to a material that significantly reduces the friction felt between a wet bar and the skin when present at relatively low levels (typically less than 1.5% based on the total weight of the bar composition). Most suitable slip modifiers are used alone or in combination at levels of 1% or less, preferably 0.05 to 1%, more preferably 0.05 to 0.5%.

[0103] Suitable slip improvers include petrolatum, waxes, lanolin, polyalkanes, polyolefins, polyalkylene oxides, high molecular weight polyethylene oxide resins, silicones, polyethylene glycols, and mixtures thereof.

[0104] Up to 3% free fatty acids (FFA) (e.g., coconut fatty acid, PKO fatty acid, lauric acid) are commonly used in soap bars to improve overall quality and processing. Free fatty acids above 3% can result in a soft, sticky material and can negatively affect one or more physical characteristics. In at least one form, the level of FFA in the composition of the present invention is from 0.05 to 3%, preferably from 0.1 to 2%, more preferably from 0.1 to 1.5% by weight.

[0105] A variety of test methods have been used to determine the properties of soap compositions.

[0106] The test method is a hardness test protocol, which uses a 30° cone probe that penetrates to a depth of 15 mm. Another test is the wear rate (RoW), which is related to the amount of material lost by a soap bar product under controlled conditions. These conditions for use roughly simulate the way consumers use the product. Further tests are conducted to examine the extent of physical damage that may (or may not) be caused by the rinsing and drying sequence of the bar. Yet another test is to determine "mushiness", which is defined as the jelly-like, creamy material formed when a toilet soap bar absorbs water. The Mush Immersion Test gives a numerical value for the amount of mush formed on the bar.

[0107] All of the above test methods are described in US 20190016994A1 (Unilever).

[0108] Method of the present invention

[0109] The method of the present invention comprises a first step of heating a fat blend comprising lauric fatty acids and saturated and unsaturated non-lauric fatty acids to 60 to 80° C. in a blending tank, wherein the iodine value of the fat blend is 44 to 58 g / iodine per 100 g. The main components of a typical mixer are a jacketed barrel, an axial rotating shaft passing through the center of the barrel (longitudinal direction), a plow-shaped blade mounted on the axial shaft, and a chopper. The plow and the high-speed chopper are mixing elements. Since the gap between the plow surface and the barrel is about 3 to 8 mm, the material is significantly sheared during mixing. A typical mixer has a barrel capacity of 60 liters, a plow rpm of 200 and a chopper rpm of 3000. The ratio of the plow area to the barrel volume is about 0.002 cm -1 .

[0110] About one third of the blend from the melt tank was then transferred to a blending tank maintained at 60 to 80 °C.

[0111] Alternatively, the process may be carried out in any mixer conventionally used in soap making. Preferably a high shear kneading mixer is used. Preferred mixers include kneading elements of the Σ-type, multiwiping overlap, single curve or double arm. Double arm kneading mixers may be overlapping or tangential in design. Alternatively, the present invention may be carried out in a helical screw stirred vessel or a multi-head metering pump / high shear mixer and spray dryer combination, just as in conventional processes.

[0112] The next step involves adding at least one reactant from the first set of reactants consisting of a water-soluble polycarboxylic acid, a water-soluble salt of such an acid, calcium chloride, a borate, or OHC(CH2)nCHO (where n=2 to 6) while maintaining the temperature between 60°C and 80°C.

[0113] The third step involves adding alkali (preferably under shear) to saponify the fat blend. Saponification is preferably carried out to an extent of 80 to 100%. Preferably an aqueous solution or dispersion of the alkali is used. More preferably, the alkali is caustic soda. Alternatively, any other suitable alkali may be used in an easily calculated stoichiometric amount. Due to the exothermic nature of the saponification reaction, the temperature of the reaction mass increases. Preferably a portion of the total alkali is introduced into the mixer in aqueous form.

[0114] The next step involves adding at least one of the second group of reactants consisting of a polyol, an alkaline silicate or a cellulose derivative under shear for in situ production of the hydrogel by chemical crosslinking of the functional groups of the first group of reactants with the corresponding reactive functional groups of the second group of reactants, wherein the temperature is maintained in the range of 90 to 110° C. and wherein steps (ii) and (iv) are interchangeable. It is preferred that the at least one of the second group of reactants is added after complete saponification of the fat blend.

[0115] The degree of saponification is preferably checked by testing the sample using an indicator such as phenolphthalein. The degree of saponification (neutralization) may also be checked periodically using pH test paper, a pH meter, or any other suitable device or technique known in the art.

[0116] Preferably, the fat blend comprises 10 to 20 parts by weight of lauric fatty acids, 35 to 50 parts by weight of saturated non-lauric fatty acids and 20 to 45 parts by weight of unsaturated non-lauric fatty acids, wherein the sum of all fatty acids is 100 parts by weight. Preferably, the unsaturated non-lauric fatty acids are obtained from at least one of tallow, lard, soybean oil, sunflower oil, rice bran oil, linseed oil, olive oil, rapeseed oil, peanut oil or fish oil, so that the iodine value of the fat blend is 44 to 58 g / iodine per 100 g of the blend.

[0117] Further disclosed is a method of preparing a soap composition comprising the steps of:

[0118] i) heating a fat blend comprising lauric fatty acids and saturated and unsaturated non-lauric fatty acids to 60 to 80° C. in a blending tank, wherein the fat blend has an iodine value of 44 to 58 g / iodine per 100 g;

[0119] ii) adding alkali to saponify the fat blend; and

[0120] iii) adding to the saponified material of step (ii) a hydrogel prepared by mixing at least one reactant from a first group of reactants consisting of a water-soluble polycarboxylic acid, a water-soluble salt of such an acid, calcium chloride, a borate or OHC(CH2)nCHO, wherein n=2 to 6, and at least one reactant from a second group of reactants consisting of a polyol, an alkaline silicate or a cellulose derivative, wherein after the addition of the hydrogel, the temperature is maintained in the range of 90 to 110°C.

[0121] In this alternative method, the hydrogel is prepared separately and blended or mixed with the saponified material.

[0122] The following examples illustrate the invention by way of non-limiting embodiments.

[0123] Example

[0124] A series of soap compositions (slim bars) were prepared in a plowshare shear mixer wherein different combinations of reactants formed hydrogels as further disclosed.

[0125] A weighed amount of hot (60-65°C) blend with the desired iodine value is added to a melting tank. About one-third of the molten blend is transferred to a plow shear mixer (PSM) and the temperature of the PSM is maintained at 80°C. An appropriately weighed amount of an aqueous solution of the first component forming a hydrogel is added to the PSM. An aqueous solution of caustic soda is then added followed by 1 / 3 of the total glycerol and shearing is applied. This step is repeated and the entire amount of blend, caustic soda and glycerol are added in this manner. The sample is tested to check the degree of saponification. Thereafter, a chelating agent is added followed by an aqueous solution of the second component forming a hydrogel and the contents are mixed thoroughly. The composition is passed through a noodle machine to obtain soap strips.

[0126] TFM is 70% by weight. The formula is shown in Table 1.

[0127] Table 1

[0128]

[0129] Further details on the fat blend / saponified fatty material (including IV) are as follows:

[0130] C1:IV 40

[0131] C2:IV 48

[0132] 1:IV 48

[0133] 2:IV 48

[0134] 3:IV 48

[0135] The iodine value of the fat blend / saponified fat material is determined by standard Wij's method. As used herein, the term "iodine value" is used as a general term for the measure of the unsaturation of the oil and is expressed as centigrams of iodine absorbed per gram of sample (% iodine absorbed). The higher the iodine value, the more unsaturated double bonds are present in the oil, and therefore the oil is more susceptible to oxidation through the double bonds. The iodine value is determined using Wij's method (as provided in American Oil Chemists' Society (AOCS) Official Method Tg1a-64, 1-2 pages, Official Methods and Recommended Practices of the American Oil Chemists' Society, Second Edition, D. Firestone ed., AOCS Press; Champaign, 1990, revised in 1990).

[0136] The elongated bars of Example 1 were used to prepare the corresponding soap bars. For example, elongated bars of composition C1 were used to prepare soap bars of composition C1B, etc. The details of the soap bar compositions are shown in Table 2.

[0137] Table 2

[0138]

[0139] The soap bars of Table 2 were subjected to some tests according to the methods described above. The soap composition of C2B was soft and pasty, and no further parameters were tested. The observations are summarized in Table 3.

[0140] Table 3

[0141]

[0142] The data show that bars 1B, 2B and 3B are almost as hard as bars that do not contain hydrogel and are not prepared according to the process of the present invention, despite the use of high IV oils / fat in the composition. Further, while bar 1B produces less mush than the control bar of Example C1B, in the case of bars 2B and 3B the mush is again the same or almost the same as the control bar of Example C1B. The examples shown clearly show that the composition according to the present invention allows the preparation of soap bars using high iodine value oils or fatty acids, while still maintaining the important hardness and mush properties.

Claims

1. A soap composition comprising: iii) saponified fatty materials made from fat blends containing lauric fatty acids and saturated and unsaturated non-lauric fatty acids; and iv) hydrogels that are thermoreversible at 70 to 140°C; wherein the iodine value of the saponified fatty substance is 46 to 58 g of iodine per 100 g of the saponified fatty substance, the iodine value being determined by the Wijs method; wherein the hydrogel is a cross-linked reaction product of at least one of a water-soluble polycarboxylic acid or a water-soluble salt of such an acid and a cellulose derivative; And wherein the composition comprises 40 to 72% by weight TFM (total fatty matter).

2. The soap composition according to claim 1, wherein the iodine value is 46 to 56 g iodine per 100 g of the saponified fatty substance, the iodine value being determined by the Wijs method.

3. The soap composition according to any one of the preceding claims, wherein the soap composition is a ground soap composition.

4. A soap composition according to any one of the preceding claims, wherein the fat blend comprises 10 to 20 parts by weight lauric fatty acids, 35 to 50 parts by weight saturated non-lauric fatty acids and 20 to 45 parts by weight unsaturated non-lauric fatty acids, wherein the sum of all fatty acids is 100 parts by weight.

5. A soap composition according to any preceding claim, wherein the composition comprises from 0.2 to 5% by weight of hydrogel.

6. The soap composition of any one of the preceding claims, wherein the saturated non-lauric fatty acid comprises at least one of palmitic acid, myristic acid or stearic acid.

7. A soap composition according to any one of the preceding claims, wherein the unsaturated non-lauric fatty acid comprises one or more of oleic acid, linoleic acid, palmitoleic acid or linolenic acid.

8. The soap composition of claim 7, wherein the unsaturated non-lauric fatty acid is obtained from at least one of tallow, lard, soybean oil, sunflower oil, rice bran oil, linseed oil, olive oil, rapeseed oil, peanut oil or fish oil.

9. A soap composition according to any preceding claim wherein the lauric fatty acid is derived from coconut oil or palm kernel oil.

10. A soap composition according to any preceding claim, wherein the composition is in the form of bars, flakes, chips or powder.

11. A soap bar comprising a soap composition according to any one of the preceding claims.

12. A method for preparing a soap composition according to any one of claims 1 to 10, comprising the following steps: i) heating a fat blend comprising lauric fatty acids and saturated and unsaturated non-lauric fatty acids to 60 to 80° C. in a blending tank, wherein the fat blend has an iodine value of 46 to 58 g iodine per 100 g, as determined by the Wijs method; ii) adding at least one of a water-soluble polycarboxylic acid or a water-soluble salt of such an acid while maintaining the temperature between 60°C and 80°C; iii) adding alkali to saponify the fat blend; as well as iv) adding a cellulose derivative for in situ production of said hydrogel by chemical cross-linking of the functional groups of said water-soluble polycarboxylic acid or of a water-soluble salt of such an acid with the corresponding reactive functional groups of said cellulose derivative, wherein the temperature is maintained in the range of 90 to 110°C and wherein said steps (ii) and (iv) are interchangeable.

13. A method for preparing a soap composition according to any one of claims 1 to 10, the method comprising the following steps: i) heating a fat blend comprising lauric fatty acids and saturated and unsaturated non-lauric fatty acids to 60 to 80° C. in a blending tank, wherein the fat blend has an iodine value of 46 to 58 g iodine per 100 g, as determined by the Wijs method; ii) adding alkali to saponify the fat blend; as well as iii) adding to the saponified material of step (ii) a hydrogel prepared by mixing at least one of a water-soluble polycarboxylic acid or a water-soluble salt of such an acid with a cellulose derivative, wherein after adding the hydrogel, the temperature is maintained in the range of 90 to 110°C.

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