CN111511886A - High-moisture-retaining structured systems for detergent compositions - Google Patents

Abstract

The present invention relates to structured systems with hydrated sodium carbonate that retain high levels of moisture. The present invention also relates to detergent compositions, particularly detergent bars having such structured systems without compromising bar properties. It is an object of the present invention to provide detergent compositions containing such structured systems that retain high levels of moisture without adversely affecting physical appearance or other sensory attributes. We have found that the objects of the present invention can be achieved by the structured system of the present invention. In particular, it has surprisingly been found that improved structuring systems with combinations of hydrated sodium carbonate and hydrated aluminum materials, silica materials or mixtures thereof can be used to provide the ability to retain high levels of moisture without compromising physical and organoleptic properties detergent composition.

Description

High-moisture-retaining structured systems for detergent compositions

Field of Invention

The present invention relates to structured systems with hydrated sodium carbonate that retain high levels of moisture. The present invention also relates to detergent compositions, particularly detergent bars having such structured systems without compromising bar properties.

Background of the Invention

In some markets where mechanical washing machines are not common, users wash their laundry with detergent bars containing synthetic or organic surfactants and detergency builders. Users who wash fabrics by hand also use a combination of first treating the stained area of the fabric with a detergent bar to remove stubborn stains, then soaking the garment in a wash liquor prepared by dissolving detergent powder in water.

Commercially available detergent bars contain detergent actives and detergency builders along with optional ingredients such as abrasives, fragrances, alkaline salts, hardeners and bleaches. Structural systems and fillers are also present in such compositions in low amounts to replace some of the detergent actives in the bar, while retaining the desired stiffness of the bar. Some known fillers include starch, kaolin and talc.

Detergent bars, in particular, require acceptable physical strength such that they retain their structural integrity during handling, shipping and use. The stiffness of the bar is a particularly important property during and after manufacture. Inclusion of certain ingredients such as minerals to make the bars stiffer generally results in higher density bars, making the bars significantly smaller and therefore less attractive to consumers and having a gritty feel.

US2004/0102353 discloses a dimensionally stable alkaline solid block warewashing detergent using an E-shaped binder to form an alkali metal silicate combination comprising a source of sodium carbonate with an alkaline, metal corrosion resistant solids, chelating agents, surfactant packaging and other optional materials. The solid mass is dimensionally stable and highly effective in removing contaminants from vessel surfaces in utility and industrial environments. The E-form hydrate contains an organic phosphonate and a hydrated carbonate.

WO 01/42413 relates to detergent bar compositions comprising 10 to 60% by weight of detergent actives; 0.5 to 40% by weight of colloidal aluminium hydroxide-phosphate and/or aluminium hydroxide-sulfate complex (Al -complex); 0-30 wt% detergent builder; 0-60 wt% inorganic particulate material; 8 to 35 wt% water, and optionally other liquid benefit agents; and the balance, which Optionally other minor additives.

US Patent 4,427,417 discloses non-caking, granular detergent compositions suitable for use in automatic washing machines or automatic dishwashers, which are derived from hydratable particulate detergent salts or such salts with other detergent ingredients such as non-hydratable washables Mixtures of agent salts, surfactants, fillers, corrosion inhibitors, chlorine release agents, colorign agents and perfumes, in ensuring that the hydratable detergent salt is substantially fully hydrated and that the hydrated particles in the composition are agglomerated to be storage stable Prepared under conditions of dry, pourable agglomerates.

One solution for replacing such minerals without compromising the bar properties is by providing a structured system with colloidal aluminium hydroxide. Structured systems such as those disclosed in IN 177828 A (Unilever, 1997) enable soap/detergent bars with satisfactory hardness and high water and low total fatty matter (TFM) content. This application discloses a structured system with a balanced combination of aluminum hydroxide and total fatty matter (TFM) that enables the use of high water content in the bar while using TFM at low levels. This patent describes a process for the in situ production of colloidal aluminum hydroxide by reacting fatty acids with an aluminum-containing basic material such as sodium aluminate.

More recently, IN 191328 A (Unilever, 2003) describes structured systems with colloidal aluminium hydroxide-phosphate and/or aluminium hydroxide-sulfate complexes added to non-soap detergent bars which enable the bars to retain high content of water while maintaining good physical and in-use properties. Some of the structuring systems are known to use phosphates for structuring water and increasing the water content in detergent bars, but incorporating phosphates in the composition adversely affects lakes and water flow by causing eutrophication, And their use in detergent compositions has been scrutinized and regulated by the government.

The increased level of water content used to structure the bar helps to improve the in-use properties of the bar in an economical manner without affecting its physical properties. Importantly, organoleptic properties such as lather, cleaning, product feel and improved in-use economics are delivered by reducing stickiness and abrasion without altering the processability and physical properties of the bars and processing the formulation using existing equipment. This enables detergent bars to be processed by conventional manufacturing methods without changing throughput.

The use of hydrated salts as an aqueous structuring system is reported in GB 1230427 A1 (Colgate, 1971), which describes a builder detergent laundry bar that is substantially free of preformed sodium bicarbonate and has a smooth in-use feel. The detergent bar contains at least 22% by weight of a binder with starch and/or grain flour, and an alkaline builder with a salt that has been hydrated in situ in the presence of the binder. The disclosed hydrated salts include sodium carbonate, pentasodium tripolyphosphate, or mixtures thereof.

While investigating the use of hydrated salts as aqueous structuring systems for detergent bar compositions, the present inventors recognized that there are problems with any attempt to utilize hydrated salts in aqueous structuring systems in the presence of a binder. First, doughs with structured systems that include binders tend to behave like a paste, and thus detergent bars are not extrudable unless high amounts of other binders are added. In GB 1230427 A1, the addition of starch as a binder together with a hydrated salt provides a detergent bar composition with high moisture content. However, the addition of large amounts of starch did not contribute as a functional additive and took up a considerable amount of formulation gap. Furthermore, large amounts of starch can cause mold growth, which requires the addition of preservatives to avoid such growth, starch can be unstable under highly alkaline conditions within detergent compositions, and can degrade over time.

It is an object of the present invention to provide water structuring systems that retain high levels of moisture.

Another object of the present invention is to provide a high moisture detergent composition containing a structured system that retains high levels of moisture without adversely affecting physical appearance or other sensory attributes.

Yet another object of the present invention is to provide detergent bar compositions containing structured systems having low density without adversely affecting other desirable properties of the compositions, such as lathering power, stain release properties, Physical appearance or other sensory attributes.

Another object is to provide structured systems for detergent compositions that are smooth to the touch in use.

A further object is to provide a structured system for detergent bar compositions which can be produced on ordinary simple devices commonly used to produce detergent laundry bars and which can be cut substantially immediately after extrusion, and which is also very fast hardened enough to resist rough handling as occurs on conventional packaging machines.

Accordingly, there is a need for a structured system that retains high levels of moisture, functions advantageously as a builder without requiring high levels of fillers and minerals, and promotes the performance of detergent bar compositions having such structured systems in a shortened hardens over time, allowing it to be cut immediately after being extruded.

SUMMARY OF THE INVENTION

We have found that one or more of these objectives can be achieved by the structured system of the present invention. In particular, hydrated sodium carbonate surprisingly provides improved structuring systems that retain high levels of moisture content when used in combination with a structuring agent selected from hydrated aluminum materials, silica materials, or mixtures thereof . Furthermore, when used in detergent bar compositions, the structured system is capable of retaining high levels of moisture without compromising physical and sensory properties.

Accordingly, in a first aspect, the present invention provides a high moisture retention structured system for a high moisture detergent composition, the structured system comprising: i. 0.5 to 70% by weight of sodium carbonate hydrate; and

ii 0.5 to 30% by weight of a structuring agent selected from hydrated aluminum materials, silica materials, or mixtures thereof, wherein the silica materials are selected from amorphous silica, hydrated silica, hydrated silica , or a mixture thereof, and wherein the moisture content in the high moisture detergent composition is from 10% to 45%.

Similarly, according to the second aspect, the present invention provides a method for preparing the structured system of the first aspect, the method comprising the step of contacting carbonic acid or a partially neutralized water-soluble carbonate with a strong base, wherein the strong base is selected from alkali metal salts of aluminate or alkali metal silicic acids.

Similarly, according to a third aspect, the present invention provides a high moisture detergent composition comprising the structured system of the first aspect or a structured system obtainable by the method of the second aspect.

In a fourth aspect, the present invention provides a method for preparing a detergent bar composition according to the third aspect, comprising the steps of:

i. The structured system according to the first aspect is prepared in situ by mixing a strong base with carbonic acid or a partially neutralized water-soluble carbonate,

ii. adding a pre-formed detergent active to the structuring system of step (i) or preparing the detergent active in situ to form an extrudable dough; and

iii. Extruding the dough of step (ii) into a detergent bar.

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 invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including", but not necessarily "consisting of" or "consisting of." In other words, the listed steps or options need not be exhaustive. It should be noted that the examples given in the following specification are intended to illustrate the invention, but not to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Numerical ranges expressed in the format "x to y" should be understood to include both x and y. When multiple preferred ranges are described in the format "x to y" for a particular feature, it is to be understood that all ranges combining the different endpoints are also contemplated.

Detailed ways

In a first aspect, the present invention relates to a structuring system comprising hydrated sodium carbonate and at least one structuring agent selected from hydrated aluminum materials, silica materials, or mixtures thereof.

structured system

The term "structuring system" as used herein refers to a selected material or mixture of materials that retains high levels of moisture and, when added to a composition such as a detergent bar composition, has the primary purpose of making the composition The moisture retention at high levels enables the bar to retain high levels of moisture without compromising the properties of the bar.

Sodium carbonate hydrate

The structuring system of the present invention comprises 0.5% to 70% by weight of hydrated sodium carbonate.

In a preferred form of the invention, the hydrated sodium carbonate contains an amount of water in its highest hydrated state (ie, 10 moles of water per mole of sodium carbonate). Preferably, the majority of the hydrated sodium carbonate is sodium decahydrate. Preferably, at least 20 parts of the total content of hydrated sodium carbonate present in the structuring system is in its highest hydrated state, more preferably at least 60 parts, still preferably at least 70 parts, still more preferably 80 parts, further preferably 90 parts, and most preferably Preferably all hydrated sodium carbonate present in the structuring system is in its highest hydrated state.

Preferably, the hydrated sodium carbonate is fully hydrated and can absorb water such that at least 20% of its weight is water, and it has an equilibrium relative humidity of less than 60% at 25°C. In this way, it can absorb a large amount of moisture "locked away" so that it does not easily evaporate and affect the properties of the detergent bar upon storage.

Preferably, the amount of hydrated sodium carbonate in the structuring system of the present invention is at least 1 wt%, also preferably at least 2.5 wt%, further preferably at least 5 wt%, more preferably 10 wt% and most preferably, based on the weight of the structuring system At least 15 wt%, but usually no more than 60 wt%, also preferably no more than 50 wt% and most preferably no more than 30 wt%.

It is also preferred that the hydrated sodium carbonate is stable with respect to moisture loss up to 40°C. This means that when heated to 40°C, the water associated with hydrated sodium carbonate remains in a stable state, and beyond 40°C, sodium carbonate decahydrate dissolves in its own crystal water to produce a sodium carbonate solution, then this water loss and language is not stable.

structurant

The structuring system of the present invention includes a structuring agent selected from hydrated aluminum materials, silica materials, or mixtures thereof. The term structurant according to the present invention refers to a material which tends to bind water such that a certain amount of water content is maintained in a composition (eg a detergent bar composition).

Hydrated aluminum material:

The structurant according to the present invention includes a hydrated aluminum material. The hydrated aluminum material refers to an aluminum-based material having an associated water content. The hydrated aluminum material is preferably alumina hydroxide, alumina gel, or a mixture thereof. More preferably, the hydrated aluminium material is aluminium oxide hydroxide.

Preferably, the amount of hydrated aluminium material in the structuring system of the present invention is at least 1 wt%, also preferably at least 2.5 wt%, further preferably at least 5 wt%, more preferably 10 wt% and most preferably, based on the weight of the structuring system At least 15 wt%, but usually no more than 27 wt%, also preferably no more than 25 wt% and most preferably no more than 20 wt%.

The disclosed structuring system comprises 0.5 to 30 wt. % of at least one of alumina hydroxide, alumina gel, amorphous silica, hydrated silica, or mixtures thereof, more preferably at a level of 10 to 30 % by weight, the most preferred content is 15 to 30% by weight.

Silica material:

The structurant according to the present invention includes a silica material. Examples of silica materials according to the present invention include, but are not limited to, silica, silicon dioxide, various forms of silica materials including crystalline silica, amorphous silica, silicon dioxide acid salts, hydrated silica, fumed silica, precipitated silica, gel silica and colloidal silica). Preferred forms herein are amorphous silica, hydrated silica, polymers of hydrated silica, or mixtures thereof. More preferably, the silica material is hydrated silica.

Preferably, the silicates that can be used are neutral or alkaline sodium silicates with a weight ratio of SiO ₂ to Na ₂ O in the range of 1.6:1 to 3.4:1.

Preferably, the silica material may be incorporated into the structuring system at a level of 0.5% to 30%, preferably 10% to about 30%, more preferably 15% to 30% by weight of the structuring system.

It is highly preferred that the structuring system according to the present invention comprises 0.5 to 30% by weight of hydrated sodium carbonate and 0.5 to 30% by weight of hydrated alumina material.

water content

The structuring system of the present invention contains a water content of 10% to 45% by weight. In one embodiment, the structured system has a total moisture content of 12 to 45 weight percent. Preferably, the water content of the structuring system is 15% by weight, more preferably 17% by weight, more preferably 18% by weight and most preferably 20% by weight, based on the weight of the structuring system, but usually not more than 40% by weight, still preferably not more than 40% by weight More than 38% by weight and most preferably not more than 35% by weight.

The term "water content" as used herein refers to water associated with a material that retains a high water content in such a way that it can only be removed by heating. Water can be chemically bound or otherwise associated with the material such that the water content is maintained and not easily lost, eg, from the structured system or detergent compositions having the structured system.

Water content can be determined by thermogravimetric analysis (TGA) using a Parkin Elmer Thermogravimetric Analyzer TGA8000. TGA was performed by intensively heating the samples in the range of 30°C to 250°C at a heating rate of 10°C/min under _N2 atmosphere.

Method for preparing structured systems

According to a second aspect of the present invention, there is disclosed a method for preparing a structured system having the neutralization or partial neutralization of carbonic acid using a strong base selected from the group consisting of silicates, basic aluminum-containing materials, and mixtures thereof the carbonate step.

Preferably, the basic aluminium-containing material is an alkali metal salt of aluminate. The alkali metal salt of aluminate is sodium aluminate or potassium aluminate, more preferably it is sodium aluminate. Preferably, the sodium aluminate is in solution form, preferably having a solids content in the range of 30 to 75% by weight, more preferably 45 to 65% by weight, still preferably 45 to 55% by weight, more preferably 40% to 55% by weight aqueous solution. When sodium aluminate is in solid form, it has a moisture content of 4 to 35% by weight, more preferably 4 to 25% by weight. Preferably, the basic aluminium material is sodium aluminate, wherein the ratio of Al ₂ O ₃ to Na ₂ O is 0.5:1 to 1.64:1, preferably 0.8:1 to 1.55:1, more preferably 1:1 to 1.5:1 .

Preferably, the strong base may be an alkali metal salt of silicic acid, preferably sodium silicate or potassium silicate, more preferably sodium silicate. When the strong base is sodium silicate in solid form, it preferably has a moisture content of 4 to 35% by weight.

Preferably, the partially neutralized carbonate is an alkali metal bicarbonate, preferably sodium bicarbonate.

Preferably, the neutralization process comprises mixing the strong base with carbonic acid or partially neutralized carbonate, and stirring the mixture under continuous stirring to provide a homogeneous mixture, preferably for a period of 2 to 15 minutes.

During the neutralization step, it was found that the addition of a small amount of sodium aluminate to the desired amount of sodium bicarbonate resulted in rapid hydration, resulting in a heterogeneous mixture, so it is highly preferred that a small amount of carbonic acid or partially neutralized Carbonate is added to a measured amount of the strongly basic material according to the invention to obtain a homogeneous mixture.

Preferably, when the strongly basic material is sodium aluminate, a measured amount of sodium aluminate is added to the stirrer, and a small amount of carbonic acid or partially neutralized carbonate, preferably sodium bicarbonate, is added under continuous stirring until All sodium bicarbonate was added and stirring was continued further until a homogeneous anhydrous structured system according to the present invention was obtained.

The disclosed methods may preferably include the addition of other ingredients. When the sodium aluminate used is 45% pure by weight of the basic material and the remaining 55% is water, typically no additional water needs to be added during the neutralization step. If desired, additional small amounts of about 5 to 10% by weight of water may be added. During the neutralization step, a maximum of 65 wt% water may be present based on the weight of the slurry, preferably the water content in the slurry does not exceed 60 wt%, also preferably does not exceed 55 wt%, and most preferably does not exceed 50 wt%.

High Moisture Detergent Composition

In a third aspect, the present invention relates to high moisture detergent compositions comprising the structured system.

detergent actives

The disclosed high moisture detergent compositions preferably comprise 5 to 80% by weight detergent actives. More preferably, the detergent composition comprises 10 to 40% by weight of detergent actives.

Preferably, the amount of detergent actives in the high moisture detergent composition is at least 10% by weight of the detergent composition, also preferably 15% by weight, further preferably at least 20% by weight, and most preferably at least 25% by weight, but Usually no more than 55 wt%, also preferably no more than 45 wt% and most preferably no more than 35 wt%.

Preferably, the detergent active may be selected from any of anionic, nonionic, cationic, zwitterionic, amphoteric surfactants and mixtures thereof. In general, the nonionic and anionic surfactants of the surfactant system can be selected from "Surface Active Agents", Vol. 1, Schwartz & Perry, Interscience 1949, Vol. 2, Schwartz, Perry & Berch, Interscience 1958, "McCutcheon's" published by Manufacturing Confectioners Company The current edition of Emulsifiers and Detergents", or the surfactants described in "Tenside-Taschenbuch", H. Stache, 2nd edition, Carl Hauser Verlag, 1981. Preferably, the surfactant used is saturated.

Anionic surfactants:

Suitable anionic detergent compounds that can be used are generally the water-soluble alkali metal salts of organic sulfuric and sulfonic acids having alkyl groups containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl moiety of higher acyl groups . Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulfates, especially those obtained by _sulfating higher C8 to _C18 alcohols (eg from tallow or coconut oil), alkyl Sodium and potassium C ₉ to C ₂₀ benzene sulfonates, especially linear secondary alkyl C ₁₀ to C ₁₅ sodium benzene sulfonates; and sodium alkyl glyceryl ether sulfates, especially higher alcohols derived from tallow or coconut oil and derived from Those ethers of petroleum synthetic alcohols. Preferred water-soluble synthetic anionic detergent active compounds are the alkali metal (eg, sodium and potassium) and alkaline earth metal (eg, calcium and magnesium) salts of higher alkylbenzene sulfonic acids, alpha-olefin sulfonates, and their combinations with higher alkyl sulfates A mixture of salts, and higher fatty acid monoglyceride sulfates. The most preferred anionic surfactants are sodium lauryl ether sulfate (SLES) (especially preferably having 1-3 ethoxy groups), sodium _C10 - _C15 alkyl benzene sulfonate, and sodium _C12 - _C18 alkyl sulfate . Also suitable are those showing resistance to salting out as described in EP-A-328 177 (Unilever), the alkyl polyglycoside surfactants described in EP-A-070074, and the alkyl Monoglycosides. The chain of the surfactant can be branched or straight.

Other anionic detergent actives are soaps. The term soap denotes salts of carboxy fatty acids. The soap can be derived from any of the triglycerides conventionally used in soap preparation, and thus, the carboxylate anion in the soap can contain from 8 to 22 carbon atoms. Preferred soaps are _C12 - _C18 fatty acid soaps. The fatty acid soap used preferably contains from about 16 to about 22 carbon atoms, preferably in a straight chain configuration. The anion contribution from the soap is preferably 0 to 30 wt% of the total anions, more preferably 0 to 15 wt%, still more preferably 0 to 5 wt% of the total anions.

Preferably, at least 50% by weight of the anionic surfactant is selected from the group consisting _of : sodium _C11 to _C15 alkylbenzene sulfonates; and sodium C12 to _C18 alkyl sulfates. Even more preferably, the anionic surfactant is sodium _C11 to _C15 alkylbenzene sulfonates.

Nonionic Surfactant:

Suitable nonionic detergent compounds which may be used include in particular compounds having hydrophobic groups and reactive hydrogen atoms (eg aliphatic alcohols, acids, amides or alkylphenols) with alkylene oxides (especially ethylene oxide alone) or the reaction product of ethylene oxide and propylene oxide). Preferred nonionic detergent compounds are _C6 to _C22 alkylphenol-ethylene oxide condensates, typically 5 to 25EO, ie ₅ to 25 units of ethylene oxide per molecule, and aliphatic C8 to ethylene oxide condensates The condensation product of a _C18 primary or secondary linear or branched alcohol with ethylene oxide, usually 5 to 50 EO. Preferably, the nonionic surfactant is 10 to 50 EO, more preferably 20 to 35 EO. Alkyl ethoxylates are particularly preferred.

It is also possible to include cationic, amphoteric or zwitterionic detergent actives in the compositions according to the invention. Suitable cationic detergent actives that can be incorporated are alkyl substituted quaternary ammonium halide salts such as bis(hydrogenated tallow) dimethylammonium chloride, cetyltrimethylammonium bromide, benzalkonium chloride and dodecyl Methylpolyoxyethylene ammonium chloride and amine and imidazoline salts such as primary, secondary and tertiary amine hydrochloride and imidazoline hydrochloride.

Suitable amphoteric detergent-active compounds which may optionally be used are derivatives of aliphatic secondary and tertiary amines containing alkyl groups having 8 to 18 carbon atoms and aliphatic groups substituted with anionic water-solubilizing groups compounds such as sodium 3-dodecylaminopropionate, sodium 3-dodecylaminopropanesulfonate, and sodium N-2-hydroxy-dodecyl-N-methyltaurate.

Suitable amphoteric detergent-active compounds which can optionally be used are derivatives of aliphatic quaternary ammonium, aliphatic groups having 8 to 18 carbon atoms and aliphatic groups substituted by anionic water-solubilizing groups. Sulfonium and phosphonium compounds such as 3-(N,N-dimethyl-N-hexadecylammonium)propan-1-sulfonate betaine, 3-(dodecylmethylsulfonium)propan-1- Sulfonate betaine and 3-(cetylmethylphosphonium)ethansulfonate betaine.

builder

In the detergent compositions according to the present invention, the hydrated alkali metal carbonates also function as detergency builders, and preferably no further builders are added to the composition. However, if desired, small amounts of further builders may be added. Examples of such detergency builders used in the formulation are preferably inorganic, suitable builders include, for example, alkali metal aluminosilicates (zeolites), alkali metal carbonates, sodium triphosphate (STPP), pyrophosphate Tetrasodium phosphate (TSPP), citrate, sodium nitrilotriacetate (NTA) and combinations of these. Preferably, the phosphate builder is present in an amount ranging from 0 to 5 wt%, also preferably 0 to 3 wt%, further preferably 0 to 2.5 wt%, and most preferably the detergent composition does not contain any phosphate builder lotion.

Inorganic particles

Suitable inorganic particles may be selected from zeolite, calcite, dolomite, feldspar, other carbonates, bicarbonates, borates, sulfates, feldspar, talc, kaolin, saponite and polymeric materials such as polyethylene.

The most preferred inorganic particles are calcium carbonate (eg calcite), mixtures of calcium carbonate and magnesium carbonate (eg dolomite), sodium bicarbonate, sodium/potassium sulfate, sodium/potassium chloride, zeolite, feldspar, talc , kaolin, silica and soapstone.

It is conventional that detergent bar compositions contain water insoluble materials, commonly referred to as fillers that help form the structure of the bar. Clays, especially kaolin and bentonite, are conventional for this purpose. If a water insoluble detergency builder is present, this will also contribute to the level of water insoluble material. Calcite, talc, kaolin, feldspar and dolomite and mixtures thereof are particularly preferred due to their low cost and color.

Minor Additives

The detergent compositions of the present invention may optionally contain a wide variety of other materials, both soluble and insoluble. Minor and conventional ingredients are preferably selected from anti-redeposition agents such as sodium carboxymethyl cellulose, fluorescent agents, colorants, bactericides, sunscreens, humectants such as glycerol, polyethylene glycol, preservatives and fragrances , and bleaching agents, bleach precursors, bleach stabilizers, chelating agents, soil release agents (generally polymers) and other polymers, polysaccharides such as starch or modified starches and cellulose, optionally added up to 10 weight%. Enzymes, especially proteases, lipases, cellulases, mannanases and amylases, may also be included. Water-soluble salts such as sodium sulfate may be included as fillers. Water-soluble alkali metal salts of those sulphur oxoacids that are reducing agents can be included in the compositions as bleaching agents.

Preferably, the detergent compositions of the present invention have less than 5% by weight of starch or derivatives thereof, more preferably less than 3% by weight of starch or derivatives thereof, still more preferably less than 2% by weight of starch or derivatives thereof, most preferably less than 2% by weight of starch or derivatives thereof Preferably, the detergent compositions of the present invention have no starch, cellulose or modified starch added to the composition.

Water content in finished detergent compositions:

Preferably, the moisture content in the finished detergent composition is maintained at 12% to 40% by weight of the finished detergent composition, preferably 15% to 30%, more preferably 11% to 30% by weight, still more preferably 20% to 27%.

detergent bar composition

In one embodiment, the high moisture detergent composition is a shaped detergent composition formed into any shape convenient for use by the user. As is commonly used for detergent laundry bars, the cross-sectional area of the bar will typically be such that the bar can be easily held in one hand, typically above ^800mm2 , and above 15mm in thickness. The cross-sectional configuration of the strips may be, for example, rectangular, square, oval or circular.

Detergent bar compositions according to the present invention comprise from 5% to 70% by weight of structuring system, preferably, the amount of structuring system in the detergent bar compositions of the present invention, based on the weight of the detergent bar composition, is at least 15 wt %, also preferably at least 20 wt %, further preferably at least 25 wt %, more preferably 30 wt % and most preferably at least 35 wt %, but usually not more than 50 wt %, still preferably not more than 45 wt % and most preferably not more than 40% by weight.

Preferably, the detergent bar compositions of the present invention comprise at least 15%, more preferably at least about 20% and most preferably at least about 25% water by weight of the detergent bar composition. The water content can be still higher, eg, 30%, 35% or even 40% by weight of the detergent bar composition, but generally does not exceed about 60%, preferably does not exceed about 55%, more preferably does not exceed about 50% %.

The water activity of the detergent bar composition is preferably in the range of 0.779 to 0.788 when measured at a temperature of 45°C. Water activity is a measure of the loss of moisture encountered from a substance during storage. It is expressed in terms of relative humidity (%) and is measured using a water activity meter (eg TH 200 Thermo constanter from Novasina).

An essential feature of the present invention is that the combination of a structuring agent selected from hydrated aluminum materials, silica materials, or mixtures thereof, together with hydrated sodium carbonate, helps to improve water structuring, thus allowing water to remain in the structuring system, further when the structure is When the structuring system is incorporated into a detergent bar composition, the structuring system provides instant hardening of the bar, preferably within 1 hour of extrusion.

Further, without being bound by theory, crystallization and recrystallization in the presence of hydrated alumina materials and/or silica materials is believed to be responsible for the accelerated formation of hydrated sodium carbonate and the rapid formation of hydrates, even in the presence of large amounts of water , thus providing the desired bar properties as disclosed in the present invention.

Solid free-flowing detergent compositions

In another embodiment, the high moisture detergent composition is in the form of a solid free flowing detergent composition comprising particulate, powder or granular compositions. Solid free-flowing detergent compositions can be prepared by any method well known to those skilled in the art. The base powder of the detergent composition can preferably be prepared by spray drying or the non-tower route. Base powders for detergent compositions typically contain detergent actives, builders, polymers and fillers. The prepared base powder is typically post-dose with the heat sensitive ingredients and fillers used to formulate the composition. The structured systems of the present invention with high levels of moisture content can be used to replace fillers added in the post-dosing stage without compromising the free-flowing and anti-caking properties desired by the user.

Solid free-flowing detergent compositions with structured systems according to the present invention further provide the benefit of using less chemical-based fillers, providing products with low bulk densities compared to compositions containing chemical-based fillers Powders prepared by the column-free approach provide improved flow and enable formulators to deliver concentrated products without causing changes in user habits.

The solid free-flowing detergent compositions according to the present invention comprise from 25% to 60% by weight of structuring systems, preferably, the amount of structuring systems in the detergent compositions of the present invention, based on the weight of the detergent composition, is at least 30% by weight, also preferably at least 35% by weight, further preferably at least 40% by weight, more preferably 45% by weight and most preferably at least 65% by weight, but usually not more than 60% by weight, still preferably not more than 55% by weight and most preferably not more than 50% by weight.

Similar to detergent bars, solid detergent compositions such as described herein are also added to solid detergent compositions in amounts that serve the purpose of providing optimum flow characteristics. However, fillers are known to be included at higher levels to formulate detergent compositions at optimum cost. Fillers are added to the insoluble inclusions in the composition, making the composition less attractive to the end user. It is desirable to remove these fillers to provide a quality product that does not cause greying of the fabric and increase the environmental impact of the product. Thus, replacing fillers with the structured systems of the present invention provides the benefit of achieving detergent compositions with lower levels of insolubles and with good powder properties such as flow characteristics. Replacing the filler with a structured system also delivers the desired low density to the detergent composition, enabling the composition to deliver the desired level of actives without changing user habits; the volumetric dosage of the composition is unchanged.

Preferably, the solid free flowing detergent compositions of the present invention comprise a water content of at least 11%, more preferably at least about 15% and more preferably at least about 25% by weight of the detergent composition. The level of water content can be still higher, such as 30%, 35% or even 40% by weight of the detergent composition, but generally does not exceed about 60%, preferably does not exceed about 55%, more preferably does not exceed about 50% %.

Method for Making a High Moisture Detergent Bar Composition According to a third aspect, there is provided a method for making a detergent bar composition of the present invention, the method comprising the steps of:

i. In situ preparation of the structured system according to the first aspect by mixing a strong base with carbonic acid or a partially neutralized water-soluble carbonate;

ii. adding the preformed detergent active to the structuring system of step (i) or preparing the detergent active in situ to form an extrudable dough; and,

iii. Extruding the dough of step (ii) into a detergent bar.

Preferably, the additional ingredients are added to the dough prior to the extrusion step. Preferably, the method for preparing the detergent bar composition involves in situ formation of hydrated sodium carbonate.

In situ formation of hydrated sodium carbonate involves the step of mixing a strong base with carbonic acid or a carbonic acid precursor, which may be a partially neutralized water-soluble carbonate. Preferably, a strong base in the range of 2 to 25 parts is mixed with 5 to 45 parts of carbonic acid or carbonic acid precursor, which may be a partially neutralized water-soluble salt thereof.

The strong base may preferably be selected from basic aluminium-containing materials, preferably aluminates. Still more preferred are alkali metal salts of aluminate, alkali metal silicic acids, or mixtures thereof. Preferably, the alkali metal is selected from sodium, potassium, more preferably sodium. Preferably, the strong base is sodium aluminate or sodium silicate, with sodium aluminate being the most preferred.

The sodium aluminate preferably has a solids content of 15 to 55%, preferably the ratio of Al ₂ O ₃ to Na ₂ O is in the range of 0.5 to 1.55:1.

In the next step in the preparation of the detergent bar composition, the detergent active may be added in acid form or in the form of a neutralized salt. When the detergent active is added in acid form, neutralization of the detergent active by the strong base is achieved prior to the addition of the carbonic acid, after the reaction of the strong base and the carbonic acid, or simultaneously with the addition of the carbonic acid. In the above, a partially neutralized water-soluble carbonate can also be used instead of carbonic acid.

Mixing and neutralization is carried out in any mixer conventionally used in soap/detergent preparation, and is preferably a high shear-kneading mixer. Preferred mixers include plowshare mixers, mixers with sigma-type kneading elements, multiwiping overlap, simple curve or dual-arm mixers. Dual-arm kneaders are available in stacked or tangential designs.

Preferably, the partially neutralized water-soluble carbonate is an alkali metal bicarbonate. Preferably, the alkali metal is sodium or potassium, more preferably sodium.

Next, the dough formed is preferably cooled by opening to the atmosphere or passing through a cold roll mill. Preferably, the cold roll mill has three or five horizontal parallel, closely spaced, driven counter rotating rolls conventionally used for grinding soap or with an internal cooling mechanism. The retention time on the mill is preferably about 5 to 10 seconds, during which time the temperature of the mixture is lowered to about 25 to 30°C.

The next step involves extruding the dough, in which the dough is fed to a conventionally constructed molding press with a pair of counter-rotating worms in a single cooling barrel equipped with a conical extrusion head, where Its outlet is an extrusion die maintained at a temperature of 25 to 30°C. The molding press has a usual fixed perforated plate mounted relative to the outlet end of the worm at the inlet to the conical extrusion head so that material is forced through the perforations of the plate, but this plate can be omitted. At a temperature of 25 to 30°C, the molded material appeared as a continuous rod with a rectangular cross-section (7.6 cm x 3.9 cm, lying flat on its wide side) corresponding to a rectangular extrusion opening in the die.

The extruded sticks are cut directly (eg, 3 seconds after extrusion) to produce individual detergent bars having the same cross-section as the sticks, each 10 cm long. Although the stick is soft, it can be cut smoothly using a continuously vertically moving cutter without being significantly distorted by the action of the cutter blade.

Thereafter, preferably, the detergent bar is continuously passed through a hand-held conveyor belt maintained at a temperature of 15 to 20°C (or, if desired, a cooling tunnel may be used). The bars are sufficiently stiff to be compressed (in a well known manner using a soap press), wrapped in paper and packaged, or wrapped and packaged without compression. Both when freshly prepared and after curing, the bars are hard and firm, and have a smooth feel in use.

The invention will now be explained in more detail using non-limiting examples of compositions according to the invention.

Example

Example 1: Preparation of a structuring system according to the invention

To prepare the structured system, 160 grams of a sodium aluminate solution containing a solids content of 45% by weight and about 55% by weight of water was placed in a plastic beaker. To the sodium aluminate solution, 200 grams of sodium bicarbonate powder was slowly added and the mixture was continuously stirred with a stainless steel spatula. Initially, following the addition of sodium bicarbonate, the mixture is a rigid thin slurry that builds up after about 4 to 6 minutes. As the reaction progresses, the temperature of the mixture increases and so does the rigidity to create a structured system. The structuring system is in dry form, has a bound water content of about 10 to 45% by weight, and comprises hydrated sodium carbonate and alumina hydroxide (a hydrated aluminum material).

Determination of bound water content by thermogravimetric analysis: The bound water content in structured systems was measured using a Parkin Elmer Thermogravimetric Analyzer TGA8000. A specified amount of the prepared structured system of Example 1 was placed in the sample reservoir of the instrument and heated from 30°C to 250°C at a rate of 10°C/min. The sample weight decreased due to moisture loss, the sample weight loss from 40°C was recorded, and the amount of bound water content (wt %) was determined.

The amount of bound water content of the structured system prepared according to Example 1 was 35% by weight.

Example 2: Preparation of high moisture detergent bar compositions according to the present invention

Method I : For the preparation of 100 kg batches of high moisture detergent bars according to the invention, a 31.05 wt. % sodium aluminate solution containing 45 wt. % solids content and the remaining 55 wt. % water was placed in a sigma mixer. Next, 38 wt% sodium bicarbonate powder was slowly added to the sigma mixer with continuous mixing for a duration of about 10 to 15 minutes, during which time the temperature of the mixture increased and the initial emulsion slurry gradually hardened into a rigid structured system.

To the resulting structured system, 17.55% by weight of the acid precursor of LAS with 90% purity was added and mixing was continued for 5 minutes to completely neutralize the acid precursor of LAS. Thereafter, inorganic fillers (4 wt% feldspar and 4 wt% hydrous magnesium silicate) were added and mixed for 2 to 4 minutes to form a uniform mass. Calcium hydroxide and alkaline sodium silicate were added to the homogeneous mass and mixed for 2 minutes. Other minor ingredients such as flavors, dyes, colorants are then added and mixed well to obtain an extrudable dough. The dough is cooled by leaving it open to the atmosphere or running through a chill roll mill. Thereafter, the dough is passed through an extruder, formed into shaped sticks, and cut directly (eg, 3 seconds after extrusion) to produce individual detergent bars having the same cross-section as the sticks , each with a length of 10.3 cm.

Although the rod is soft, it can be cut smoothly without being substantially distorted by the action of the cutter blade. Both when freshly prepared and after aging, the bars are hard and firm, and have a smooth feel when used.

Method II: In an alternative method for making a detergent bar with a structured system according to the present invention, a 31.05 wt% sodium aluminate solution with a solids content of 45 wt% and a remaining 55 wt% water was placed in sigma mixing in the device. Next, 17.55 wt% LAS acid precursor with 90% purity was added and mixing was continued for 5 minutes to completely neutralize the LAS acid precursor. Thereafter, the 38 wt% sodium bicarbonate powder was slowly added to the sigma mixer with continuous mixing for a duration of about 10 to 15 minutes, during which time the temperature of the mixture increased and the initial emulsion slurry gradually hardened into a rigid structured system. Then, inorganic fillers (4 wt% feldspar and 4 wt% hydrated magnesium silicate), calcium hydroxide and alkaline sodium silicate and other minor ingredients such as fragrances, dyes, colorants were added as described above and mixed for about 6 minutes An extrudable dough was obtained and prepared into a detergent bar as detailed above.

Determination of Penetration Value:

Penetration values represent the hardness of the strip measured using a cone penetrometer, details of typical instruments and measurement methods are given below.

conical penetrometer

Manufacturer: Adair Dutt & Company, Bombay

Measuring range: 0 to 40mm

Validation range: 20 in 5 steps Measurement procedure: The entire substance (including the penetrator needle and standard weight) resting on the test sample is allowed to fall freely on the test sample, the penetrator needle pierced for a specified period of time Enter the test substance to a specified distance, and the distance is recorded as 0.1mm. At least 3 readings were averaged and provided in Table 1 below.

The water content and hardness of the detergent bars according to the present invention prepared using Method I are reported in Table 1 .

Table 1

The sensory attributes of detergent bars according to the present invention were also evaluated using the test methods given below, and the results of the evaluations were recorded and provided in Table 1a below.

Feeling/Gritty: Following the wash down protocol technique, the feeling of grit was assessed by feel using a group of trained panelists. The wash-off protocol consisted of holding a detergent bar under running water and evaluating the surface feel of the bar by rubbing the bar 40 times with hand rotation. Underwater smoothness of the strips when washed off was evaluated by trained panelists on a scale of 1 to 10, where 1=musty, 2=slimy, 3=slippery, 4=very very smooth, 5=smooth, 6=slightly draggy, 7=draggy, 8=slightly gritty, 9=very gritty / sandy, 10=very sandy. Detergent bars of acceptable quality typically have a sensory score in the range of 7.8 to 8.

Abrasion/% Abrasion: To determine strip wear, the original weight of the strip was taken. A single wash down protocol was followed in which the desized 100% woven cotton fabric was immersed in a bowl of water (water hardness 6FH Ca:Mg-2:1). Then, hold the fabric in your hands and allow it to drain for 10 seconds. After this, the fabric is laid flat in an enamel dish. The test strip was briefly immersed in 2.0 L of water (6FHCa:Mg 2:1) and the first side of the strip was rubbed 5 times along the length of the wet fabric so that the rubbed areas did not overlap. Thereafter, the wet fabric was turned over and the strip was rubbed five more times along the length of the wet fabric with the same side of the strip. The strip was briefly immersed in water again, then the second side of the strip was rubbed along the length of the second wet fabric in a similar operation to the first fabric. The weight loss after the above procedure is recorded and expressed as: a) weight loss in grams, and b) % loss by weight. The above experiments were performed in triplicate.

Sogginess: To assess the sogginess of the bars, the abrasion test protocol described above was followed. Thereafter, trained user panelists rated the strip by feeling the first and second sides of the strip with four fingers and rating the wetness on a scale of 0 to 8, where 0=dry, 1=wet (moist) but not sticky, 2=wet but not sticky, 3=slightly sticky, 4=sticky, 5=slightly mushy, 6=mushy, 7=watery, 8=very watery. Record the score provided.

Density: Measure by standard methods and calculate the density of the bars using:

Table 1a

Wear (gm loss/piece) 118.55 Wear % 46.76 Top surface wetness - total 11.00 Soakability of the bottom surface - total 10.00 Soak in water - last day underside 3.00 Penetration value 2.00 gritty 8.00 Exterior no weathering Density of strips (gm/cm³) 1.68 to 1.75

Example 3: Evaluation of Detergent Bar Compositions According to the Invention and Comparative Detergent Bar Compositions

For the preparation of a comparative detergent bar (Composition A), 36 wt% acid precursor of LAS anionic surfactant was mixed with 25.75 wt% sodium carbonate in a sigma mixer to form a neutralized paste to 10 wt% water and 28.1 wt% cornstarch were added to the batter to form a dough. The dough is cooled by keeping it open to the atmosphere. Once cooled, the dough is passed through an extruder and formed into shaped bars and cut directly (eg, 3 seconds after extrusion) to produce individual detergent bars having the same cross-section as the bars, Each is 10.3cm long. The final bar compositions are provided in Table 3.

For the preparation of a detergent bar according to the invention (Example 3), a 30% by weight sodium aluminate solution with a solids content of 45% by weight and a remaining 55% by weight of water was placed in a sigma mixer. Next, the 34 wt% sodium bicarbonate powder was slowly added to the sigma mixer with continuous mixing for a duration of about 10 to 15 minutes, during which time the temperature of the mixture increased and the initial emulsion slurry gradually hardened into a rigid structured system. 36% by weight of the acid precursor of LAS was added to the formed structured system and mixing was continued for 5 minutes to completely neutralize the acid precursor of LAS and the dough obtained was allowed to cool by keeping it open to the atmosphere . Once cooled, the dough is passed through the extruder and formed into shaped bars and cut directly (eg, 3 seconds after extrusion) to produce individual detergent bars having the same cross-section as the bars, each 10.3cm long. The final bar compositions are provided in Table 3.

Measurement of Penetration Value (PV):

Penetration values represent the stiffness or stiffness of the strip and are determined using a standard cone penetrometer (Petrotest PNR10). To measure penetration values, the tip of the penetrometer is adjusted on the flat surface of the sample detergent bar so that it makes point contact with the surface. Use the side lift-lit light to adjust precisely so that the shadow of the tip coincides with the tip itself. After completing the adjustment, adjust the scale to zero and turn on the instrument. The instrument measures the penetration depth of the needle for a duration of 5 seconds. Penetration values were recorded and the above process repeated three times at different points on the surface of the strip.

Moisture content measurement:

The moisture content of the detergent bar was determined by powdering the detergent bar, maintaining 1 gm of the powdered material on the pan of a hot air oven, and heating to 130°C. The material is held for a period of 1 hour or until its weight is constant. The weight of the powder material at the end of 1 hour was measured and the % moisture content was calculated from the weight loss calculations, provided in Table 1.

Moisture content, hardness of the bars were determined using the methods described above, and the reported values are presented in Table 3.

table 3

Element Composition A (wt%) Example 3 (wt%) LAS sodium 39.12 39.12 Sodium carbonate 21.28 27.89 Alumina (Al₂O₃) 0 9.43 water 11.5 23.56 corn starch 28.1 0 total 100 100 Moisture content (wt%) 11.50 17.20 Penetration value (PV) (mm) Reading 1 (at 155gm wt) 1.86±0.04 0.8±0.04 Reading 2 (at 105gm wt) 1.72±0.06 0.32±0.07

The data presented in Table 3 shows that it is possible to prepare detergent bar compositions with good physical and in-use properties, while structuring and retaining higher levels of water in the bar. Detergent bar compositions according to the present invention also retain higher levels of moisture while scoring higher on hardness than the detergent bars prepared according to the prior art (Composition A).

Example 4: Powder detergent composition comprising a structured system according to the present invention

A spray-dried base powder having the composition as provided in Table 4 was prepared. For the preparation of a comparative spray-dried powder detergent composition (Composition B), the specified amount of sodium carbonate was added to the spray-dried base powder prepared as given in Table 4. Similarly, to prepare a spray-dried powder detergent composition according to the present invention (Example 4), the specified amount of the structured system prepared according to Example 1 containing a moisture content of 42% by weight was added to the composition as given in Table 4 Preparation of spray-dried base powder.

The moisture content and flowability of the two powder detergent compositions were evaluated and are provided in Table 4.

Table 4

The data presented in Table 4 shows that the composition with the structured system prepared in accordance with the present invention (Example 4) has a higher moisture content than the comparative detergent composition (Composition B) and is still free flowing .

Claims (12)

1. A high moisture retaining structuring system for use in detergent compositions, said structuring system comprising:

0.5 to 70% by weight of hydrated sodium carbonate; and the combination of (a) and (b),

0.5 to 30% by weight of a structuring agent selected from hydrated aluminum materials, silica materials or mixtures thereof, wherein the hydrated sodium carbonate comprises sodium carbonate decahydrate, wherein the silica materials are selected from amorphous silica, hydrated silica, polymers of hydrated silica, or mixtures thereof, and wherein the structuring system has a total moisture content of 10 to 45% by weight.

2. A structuring system according to claim 1 wherein the structuring system has a total moisture content of from 12 to 45% by weight.

3. A structuring system according to claim 1, wherein the hydrated aluminum material is selected from alumina hydroxide, alumina gel, or mixtures thereof.

4. A process for the preparation of a structuring system according to any of the preceding claims 1 to 3, comprising the step of contacting a carbonated or partially neutralized water soluble carbonate with a strong base, wherein the strong base is selected from alkali metal aluminates or alkali metal silicates.

5. The method of claim 4, wherein the strong base is aqueous sodium aluminate having a solids content in the range of 40 to 55 wt.% or sodium silicate in solid form having a moisture content of 4 to 35 wt.%.

6. The method according to any one of the preceding claims 4 to 5, wherein the partially neutralized water soluble carbonate is a bicarbonate of an alkali metal.

7. A high moisture detergent composition comprising a high moisture retaining structuring system as defined in any of the preceding claims 1 to 3 or obtainable by a process according to any of the preceding claims 4 to 6, wherein the moisture content in the high moisture detergent composition is from 12% to 40%.

8. The high moisture detergent composition of claim 7, wherein the total moisture content in the finished detergent composition is from 11 wt% to 30 wt%.

9. A high moisture detergent composition according to claim 7 or 8 which is a detergent bar composition comprising from 5 to 80 wt% detergent active.

10. A high moisture detergent composition according to claim 7 or 8 which is a particulate, powder or granular composition comprising from 25 to 60 wt% of the structuring system.

11. A process for preparing a detergent bar composition according to claim 100 comprising the steps of:

i. preparing in situ a high moisture retaining structuring system according to any of the preceding claims 1 to 3 by the process of claim 4;

(ii) adding a pre-formed detergent active to the structuring system of step (i) or preparing the detergent active in situ to form an extrudable dough; and

(iii) extruding the dough of step (ii) into a detergent bar.

12. A process for the preparation of a detergent bar composition according to claim 11 wherein the detergent active is prepared in situ by neutralising the acid precursor of the surfactant with a strong base before or after the addition of carbonic acid or a partially neutralised water soluble carbonate salt in step (i).