CN111511886B

CN111511886B - High moisture retaining structuring system for detergent compositions

Info

Publication number: CN111511886B
Application number: CN201880080691.7A
Authority: CN
Inventors: A·班加尔; S·S·希巴雷; N·苏布拉马尼亚姆
Original assignee: Unilever NV
Current assignee: Unilever IP Holdings BV
Priority date: 2017-12-12
Filing date: 2018-12-10
Publication date: 2021-06-01
Anticipated expiration: 2038-12-10
Also published as: CN111511886A; WO2019115435A1

Abstract

The present invention relates to structuring systems with hydrated sodium carbonate which retain a high level of moisture. The invention also relates to detergent compositions, in particular detergent bars having said structuring system without compromising the bar properties. It is an object of the present invention to provide detergent compositions containing said structuring system which 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 structuring system of the present invention. In particular, it has surprisingly been found that improved structuring systems having a combination of hydrated sodium carbonate and hydrated aluminum materials, silica materials or mixtures thereof can be used to provide detergent compositions capable of retaining high levels of moisture without compromising physical properties and sensory attributes.

Description

High moisture retaining structuring system for detergent compositions

Technical Field

The present invention relates to structuring systems with hydrated sodium carbonate which retain a high level of moisture. The invention also relates to detergent compositions, in particular detergent bars having said structuring system without compromising the bar properties.

Background

In some markets where mechanical washing machines are not common, consumers use detergent bars containing synthetic or organic surfactants and detergency builders for laundry washing. Users who wash fabrics by hand also use the following combinations: the stained area of the fabric was first treated with a detergent bar to remove stubborn stains, followed by soaking the laundry in a wash liquor prepared by dissolving detergent powder in water.

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

Detergent bars, in particular, require acceptable physical strength so that they retain their structural integrity during handling, transport and use. The hardness of the bars is a particularly important property during and after production. The inclusion of certain ingredients, such as minerals, to make the bar stiffer generally results in a higher density bar, which is significantly smaller and therefore less appealing and gritty to the consumer.

US2004/0102353 discloses a dimensionally stable alkaline solid block warewashing detergent that uses an E-shaped binder to form a solid comprising a source of sodium carbonate having alkalinity, an alkali metal silicate composition to protect the metal from corrosion, a sequestrant, a surfactant package, and other optional materials. The solid cake is dimensionally stable and highly effective in removing soil from the surface of the ware in public facilities and industrial environments. The E-form hydrate comprises an organic phosphonate and a hydrated carbonate.

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

US patent 4,427,417 discloses non-caking, granular detergent compositions suitable for use in automatic washing machines or automatic dishwashing machines, prepared from hydratable particulate detergent salts or mixtures of such salts with other detergent ingredients such as non-hydratable detergent salts, surfactants, fillers, corrosion inhibitors, chlorine release agents, colorants (colorings) and perfumes, under conditions which ensure that the hydratable detergent salts are substantially fully hydrated and that the hydrated granules in the composition agglomerate into storage stable, dry pourable agglomerates.

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

Recently, IN 191328A (Unilever, 2003) described structuring systems with colloidal aluminium hydroxide-phosphate and/or aluminium hydroxide-sulphate complexes added to non-soap detergent bars, which enabled the bars to retain high levels of water whilst maintaining good physical and IN-use properties. Some of the known structuring systems use phosphate for structuring water and increasing the water content in detergent bars, but the incorporation of phosphate in the composition adversely affects lake and water flow by causing eutrophication, and their use in detergent compositions has been under government scrutiny and regulation.

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, sensory properties such as lather, cleansing, product feel and improved economy of use are delivered by reducing softness, thickening and abrasion without altering the processability and physical properties of the bar and processing the formulation using existing equipment. This enables detergent bars to be processed by conventional manufacturing processes without changing throughput.

The use of hydrated salts as water structuring systems is reported in GB 1230427 a1(Colgate, 1971), which describes a building detergent laundry bar, substantially free of preformed sodium bicarbonate, and having a smooth feel in use. The detergent bar comprises at least 22 wt% of a binder having starch and/or cereal flour, and an alkaline builder having salts which have been hydrated in situ in the presence of the binder. The hydrated salts disclosed include sodium carbonate, pentasodium tripolyphosphate, or mixtures thereof.

When studying the use of hydrated salts as water structuring systems for detergent bar compositions, the present inventors have realised that there are problems with any attempt to utilise hydrated salts in a water structuring system in the presence of a binder. First, doughs (dough) with a structuring system comprising a binder tend to behave like a paste, and therefore 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 hydrated salts provides a high moisture containing detergent bar composition. However, the addition of large amounts of starch does not contribute as a functional additive and takes up a considerable amount of formulation space. Moreover, large amounts of starch can cause mold growth, preservatives need to be added to avoid such growth, starch can be unstable under the highly alkaline conditions within detergent compositions, and can degrade over time.

It is an object of the present invention to provide a water structuring system that retains a high level of moisture.

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

It is a further object of the present invention to provide a detergent bar composition comprising a structuring system which has a low density without adversely affecting other desirable properties of the composition, such as foaming ability, soil release characteristics, physical appearance or other sensory attributes.

It is a further object to provide a structuring system for detergent compositions which is smooth to the touch in use.

A further object is to provide a structuring system for detergent bar compositions which can be produced on common simple equipment commonly used for the production of detergent laundry bars and which can be cut substantially immediately after extrusion and yet harden very quickly to a degree sufficient to resist rough handling as occurs on conventional packaging machines.

There is therefore a need for a structuring system which retains a high level of moisture, advantageously functions as a builder without the need for high levels of fillers and minerals, and promotes hardening of detergent bar compositions having the structuring system in a reduced time, enabling them to be cut immediately after being extruded.

Disclosure of Invention

We have found that one or more of these objects can be achieved by the structuring system of the present invention. In particular, when hydrated sodium carbonate is used in combination with a structuring agent selected from a hydrated aluminum material, a silica material, or mixtures thereof, the hydrated sodium carbonate surprisingly provides an improved structuring system that retains a high level of moisture content. Moreover, when used in detergent bar compositions, the structuring system is able to retain high levels of moisture without compromising physical properties and sensory attributes.

Accordingly, in a first aspect, the present invention provides a high moisture retaining structuring system for a high moisture detergent composition, said structuring system comprising: 0.5 to 70% by weight of hydrated sodium carbonate; and

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

Similarly, according to a second aspect, the present invention provides a process for the preparation of the structuring system of the first aspect, comprising the step of contacting a carbonated or partially neutralized water-soluble carbonate salt with a strong base, wherein the strong base is selected from alkali metal aluminates or silicates.

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

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

i. the structuring 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 salt,

(ii) adding a pre-formed detergent active to the structuring system of step (i) or preparing a 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 used in any other aspect of the invention. The word "comprising" is intended to mean "including", but not necessarily "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 description are intended to illustrate the present invention, and are not intended to limit the present invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Numerical ranges expressed in "x to y" format should be understood to include 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 Description

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

Structuring system

The term "structuring system" as used herein refers to a selected material or mixture of materials which retains a high level of moisture and which, when added to a composition, for example a detergent bar composition, primarily aims to retain moisture at high levels in the composition, enables the bar to retain a high level of moisture without compromising the properties of the bar.

Hydrated sodium carbonate

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

In a preferred form of the invention, the hydrated sodium carbonate contains a water content in an amount at its highest hydration state (i.e., 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 carbonates present in the structuring system are in their highest hydration state, more preferably at least 60 parts, still preferably at least 70 parts, still more preferably 80 parts, further preferably 90 parts, most preferably all hydrated sodium carbonates present in the structuring system are in their highest hydration 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 ℃. In this way, it can absorb a significant amount of water "locked away", so that it does not readily evaporate on storage and affects the properties of the detergent bar.

Preferably, the amount of hydrated sodium carbonate in the structuring system of the present invention is at least 1 wt%, still preferably at least 2.5 wt%, further preferably at least 5 wt%, more preferably 10 wt% and most preferably at least 15 wt%, but generally not more than 60 wt%, still preferably not more than 50 wt% and most preferably not more than 30 wt%, based on the weight of the structuring system.

It is also preferred that the hydrated sodium carbonate is stable with respect to moisture loss up to 40 ℃. This means that when heated to 40 ℃, the water associated with the hydrated sodium carbonate remains in a stable state, above 40 ℃, sodium carbonate decahydrate dissolves in its own water of crystallization, producing a sodium carbonate solution, which is then not stable in terms of water loss.

Structuring agent

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

Hydrated aluminum material:

the structuring agent according to the present invention comprises 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 an alumina hydroxide, an alumina gel, or a mixture thereof. More preferably, the hydrated aluminum material is an alumina hydroxide.

Preferably, the amount of hydrated aluminum material in the structuring system of the present invention is at least 1 wt.%, still preferably at least 2.5 wt.%, further preferably at least 5 wt.%, more preferably 10 wt.% and most preferably at least 15 wt.%, but generally not more than 27 wt.%, still preferably not more than 25 wt.% and most preferably not more than 20 wt.%, based on the weight of the structuring system.

The disclosed structuring system comprises at least one of alumina hydroxide, alumina gel, amorphous silica, hydrated silica or mixtures thereof in an amount of 0.5 to 30 wt.%, more preferably in an amount of 10 to 30 wt.%, most preferably in an amount of 15 to 30 wt.%.

Silicon dioxide material:

the structuring agent according to the invention comprises a silica material. Examples of silica materials according to the present invention include, but are not limited to, silica (silica), silica (silica dioxide), different forms of silica materials (including crystalline silica, amorphous silica, silicates, 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, silicates having a SiO in the range of 1.6:1 to 3.4:1 can be used₂With Na₂Neutral sodium silicate or alkaline sodium silicate in the weight ratio of O.

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

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

Water content

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

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 may be chemically bound or otherwise associated with the material such that water content is maintained and not readily lost, for example from the structuring system or detergent compositions having the structuring system.

Water content can be determined using a Parkin Elmer Thermogravimeric Analyzer TGA8000 is determined by thermogravimetric analysis (TGA). By reaction at N₂TGA is performed by intense heating of the sample at a heating rate of 10 ℃/min in the range of 30 ℃ to 250 ℃ under an atmosphere.

Process for the preparation of structuring systems

According to a second aspect of the present invention, a process for the preparation of a structuring system is disclosed having the step of neutralizing a carbonic acid or partially neutralized carbonate salt with a strong base selected from silicates, basic aluminium containing materials, and mixtures thereof.

Preferably, the basic aluminium-containing material is an alkali metal 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 the form of a solution, preferably an aqueous solution having a solids content in the range of from 30 to 75 wt.%, more preferably from 45 to 65 wt.%, still more preferably from 45 to 55 wt.%, more preferably from 40 to 55 wt.%. When the 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 alkaline aluminum material is sodium aluminate, wherein Al is₂O₃With Na₂O is in a ratio of 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 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 neutralisation process comprises mixing the strong base with carbonic acid or partially neutralised carbonate and stirring the mixture under continuous stirring to provide a homogeneous mixture, preferably for a period of 2 to 15 minutes.

In the neutralization step, it was found that the addition of a small amount of sodium aluminate to the required amount of sodium bicarbonate resulted in rapid hydration, obtaining a heterogeneous mixture, and it is therefore highly preferred to add a small amount of carbonic acid or partially neutralized carbonate to a measured amount of strong alkaline material according to the invention under continuous stirring 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 salt, preferably sodium bicarbonate, is added under continuous stirring until all sodium bicarbonate is added and stirring is further continued until a homogeneous anhydrous structuring system according to the invention is obtained.

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

High moisture detergent composition

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

Detergent active

The disclosed high moisture detergent compositions preferably comprise from 5 to 80 wt% detergent active. More preferably, the detergent composition comprises from 10 to 40 wt% of detergent active.

Preferably, the amount of detergent active in the high moisture detergent composition is at least 10 wt%, still preferably 15 wt%, further preferably at least 20 wt%, and most preferably at least 25 wt%, but typically not more than 55 wt%, still preferably not more than 45 wt% and most preferably not more than 35 wt% of the detergent composition.

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 may be selected from the group consisting of "Surface Active Agents", Vol.1, Schwartz & Perry, Interscience 1949, Vol.2, Schwartz, Perry & Berch, Interscience 1958, the current version of "McCutcheon's Emulsifiers and Detergents" published by the Manufacturing conditioners Company, or the surfactants described in "Tenside-Taschenbuch", H.Stache, 2 nd edition, Carl Hauser Verlag, 1981. Preferably, the surfactant used is saturated.

Anionic surfactant:

suitable anionic detergent compounds which may be used are typically water-soluble alkali metal salts of organic sulphuric and sulphonic acids having an alkyl group containing from about 8 to about 22 carbon atoms, the term alkyl being used for the alkyl moiety including the higher acyl groups. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially by reacting higher C' s₈To C₁₈Those obtained by sulfating alcohols (e.g. from tallow or coconut oil), alkyl C₉To C₂₀Sodium and potassium benzene-sulphonates, especially linear secondary alkyl C₁₀To C₁₅Sodium benzenesulfonate; and sodium alkyl glyceryl ether sulfates, particularly those derived from higher alcohols of tallow or coconut oil and synthetic alcohols derived from petroleum. Preferred water-soluble synthetic anionic detergent active compounds are alkali metal (e.g. sodium and potassium) and alkaline earth metal (e.g. calcium and magnesium) salts of higher alkylbenzene sulfonic acids, alpha-olefin sulfonates and mixtures thereof with higher alkyl sulfates, and higher fatty acid monoglyceride sulfates. The most preferred anionic surfactants are Sodium Lauryl Ether Sulfate (SLES) (particularly preferred having 1-3 ethoxy groups), C₁₀-C₁₅Sodium alkyl benzene sulfonate and C₁₂-C₁₈Sodium alkyl sulfate. Also applicable are those which show resistance to salting out as described in EP-A-328177 (Unilever), alkyl polyglycoside surfactants as described in EP-A-070074, and alkyl monoglycosides. The chain of the surfactant may be branched or straight.

Other anionic detergent actives are soaps. The term soap denotes salts of carboxylic fatty acids. The soap may be derived from any of the triglycerides conventionally used in soap manufacture, and thus the carboxylate anion in the soap may contain from 8 to 22 carbon atoms. Preferred soaps are C₁₂-C₁₈Fatty acid soaps. The fatty acid soaps used preferably contain from about 16 to about 22 carbon atoms, preferably in the straight chain configuration. The anionic contribution from the soap is preferably from 0 to 30 wt%, more preferably from 0 to 15 wt%, still more preferably from 0 to 5 wt% of the total anions.

Preferably, at least 50 wt% of the anionic surfactant is selected from: c₁₁To C₁₅Sodium alkyl benzene sulfonate; and C₁₂To C₁₈Sodium alkyl sulfate. Even more preferably, the anionic surfactant is C₁₁To C₁₅Sodium alkyl benzene sulfonate.

Nonionic surfactant:

suitable nonionic detergent compounds which may be used include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, such as aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide alone or together with propylene oxide. Preferred nonionic detergent compounds are C₆To C₂₂Alkylphenol-ethylene oxide condensates, usually 5 to 25EO, i.e. 5 to 25 units of ethylene oxide per molecule, and aliphatic C₈To C₁₈Condensation products of primary or secondary linear or branched alcohols with ethylene oxide, typically 5 to 50 EO. Preferably, the nonionic surfactant is 10 to 50EO, 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 may be incorporated are alkyl substituted quaternary ammonium halide salts such as bis (hydrogenated tallow) dimethyl ammonium chloride, cetyltrimethylammonium bromide, benzalkonium chloride and dodecylmethylpolyoxyethyleneammonium chloride and amine and imidazoline salts such as primary, secondary and tertiary amine hydrochlorides and imidazoline hydrochlorides.

Suitable amphoteric detergent-active compounds which may optionally be used are derivatives of aliphatic secondary and tertiary amines which contain an alkyl radical having from 8 to 18 carbon atoms and an aliphatic radical which is substituted by an anionic water-solubilizing group, for example sodium 3-dodecylaminopropionate, sodium 3-dodecylaminopropanesulfonate and sodium N-2-hydroxy-dodecyl-N-methyltaurate.

Suitable amphoteric detergent-active compounds which may optionally be used are derivatives of aliphatic quaternary ammonium, sulfonium and phosphonium compounds having an aliphatic radical of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for example 3- (N, N-dimethyl-N-hexadecylammonium) propane-1-sulfonate betaine, 3- (dodecylmethylsulfonium) propane-1-sulfonate betaine and 3- (cetylmethylphosphonium) ethanesulfonate betaine.

Builder

In the detergent composition according to the invention, the hydrated alkali metal carbonate also functions as a detergency builder, and preferably no additional builder is added to the composition. However, if desired, small amounts of further builder may be added. Examples of such detergency builders used in the formulations are preferably inorganic, suitable builders include, for example, alkali metal aluminosilicates (zeolites), alkali metal carbonates, Sodium Tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), citrates, sodium Nitrilotriacetate (NTA) and combinations of these. Preferably, the phosphate builder is present in an amount in the range of from 0 to 5 wt%, still preferably from 0 to 3 wt%, further preferably from 0 to 2.5 wt%, most preferably the detergent composition does not comprise any phosphate builder.

Inorganic particles

Suitable inorganic particles may be selected from zeolites, calcites, dolomites, feldspars, other carbonates, bicarbonates, borates, sulphates, feldspars, talcs, kaolins, saponites and polymeric materials such as polyethylene.

The most preferred inorganic particles are calcium carbonate (e.g. calcite), mixtures of calcium and magnesium carbonate (e.g. dolomite), sodium bicarbonate, sodium/potassium sulphate, sodium/potassium chloride, zeolites, feldspar, talc, kaolin, silica and saponite.

It is conventional for detergent bar compositions to comprise water-insoluble materials, commonly referred to as fillers, which help to form the structure of the bar. Clays, particularly kaolin and bentonite, are conventional for this purpose. If present, the water-insoluble detergency builder 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 colour.

Minor additives

The detergent compositions of the present invention may optionally comprise a wide variety of other materials, both soluble and insoluble. Minor and conventional ingredients are preferably selected from antiredeposition agents such as sodium carboxymethylcellulose, fluorescers, colourants, bactericides, opacifiers, humectants such as glycerol, polyethylene glycols, preservatives and perfumes, as well as bleaching agents, bleach precursors, bleach stabilisers, chelants, soil release agents (typically polymers) and other polymers, polysaccharides such as starch or modified starches and cellulose, optionally added up to 10% by weight. Enzymes, in particular proteases, lipases, cellulases, mannanases and amylases may also be included. Water soluble salts such as sodium sulphate may be included as fillers. Water soluble alkali metal salts of those sulfoxylic acids (sulphlur oxo acids) which are reducing agents may be included in the compositions as bleaching agents.

Preferably, the detergent composition of the invention has less than 5 wt% starch or derivative thereof, more preferably less than 3 wt% starch or derivative thereof, still more preferably less than 2 wt% starch or derivative thereof, most preferably the detergent composition of the invention has no starch, cellulose or modified starch added to the composition.

Water content in finished detergent composition:

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

Detergent bar composition

In one embodiment, the high moisture detergent composition is a shaped detergent composition formed into any shape convenient for the user to use.As is commonly used for detergent laundry bars, the cross-sectional area of the bar will generally be such that the bar can be conveniently held in one hand, typically above 800mm²And the thickness is higher than 15 mm. The cross-sectional configuration of the strip may be, for example, rectangular, square, oval or circular.

The detergent bar composition according to the invention comprises from 5 wt% to 70 wt% of the structuring system, preferably the amount of structuring system in the detergent bar composition of the invention is at least 15 wt%, further preferably at least 20 wt%, further preferably at least 25 wt%, more preferably 30 wt% and most preferably at least 35 wt%, but typically not more than 50 wt%, further preferably not more than 45 wt% and most preferably not more than 40 wt%, based on the weight of the detergent bar composition.

Preferably, the detergent bar composition of the present invention comprises 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 may be even higher, for example 30%, 35% or even 40%, but typically does not exceed about 60%, preferably does not exceed about 55%, more preferably does not exceed about 50% by weight of the detergent bar composition.

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 ℃. Water activity is a measure of the loss of water from a substance encountered during storage. It is expressed in terms of relative humidity (%) and measured using a water activity meter (e.g., TH 200Thermo stabilizer from Novasina).

An essential feature of the present invention is that the combination of a structuring agent selected from a hydrated aluminium material, a silica material or mixtures thereof together with hydrated sodium carbonate helps to improve the water structuring, thus retaining water in the structuring system, which further provides immediate hardening of the bar when the structuring system is incorporated into a detergent bar composition, 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 accelerating the formation of hydrated sodium carbonate and rapid hydrate formation, 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 composition

In another embodiment, the high moisture detergent composition is in the form of a solid free-flowing detergent composition comprising a particulate, powder or granular composition. The solid free-flowing detergent composition may be prepared by any method known to those skilled in the art. The base powder of the detergent composition may preferably be prepared by spray-drying or non-tower route (non-tower route). The base powder of the detergent composition typically comprises detergent active, builder, polymer and filler. The prepared matrix powder is usually post-dosed (post-dose) with heat sensitive ingredients and fillers used to formulate the composition. The structuring system 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.

The solid free-flowing detergent composition with a structuring system according to the present invention further provides the benefit of using less chemical-based filler, provides a product with a low bulk density compared to compositions containing chemical-based fillers, provides improved flowability to powders prepared by the tower-less route process, and enables the formulator to provide a concentrated product without causing a change in the user's habits.

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

Similar to detergent bars, solid detergent compositions such as those described herein are also added with some amount of filler, which serves the purpose of providing optimal flow characteristics. However, it is known that fillers are included at higher levels to formulate detergent compositions at optimal cost. Fillers are added to the insoluble content of 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 the fabric to ash and increase the environmental impact of the product. Thus, replacement of the filler with the structuring system of the present invention provides the benefit of achieving a detergent composition with a lower amount of insolubles and with good powder properties such as flow characteristics. Replacing the filler with a structuring system also delivers the desired low density to the detergent composition, enabling the composition to deliver the desired level of active without altering user habits; the volumetric dose of the composition was constant.

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 may be even higher, such as 30%, 35% or even 40%, but generally does not exceed about 60%, preferably does not exceed about 55%, more preferably does not exceed about 50% by weight of the detergent composition.

Process for making high moisture detergent bar compositionsAccording to a third aspect, there is provided a process for the preparation of a detergent bar composition of the present invention, the process comprising the steps of:

i. preparing the structuring system according to the first aspect in situ by mixing a strong base with carbonic acid or a partially neutralized water soluble carbonate salt;

(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 the combination of (a) and (b),

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

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

The in situ formation of hydrated sodium carbonate includes the step of mixing a strong base with a carbonic acid or 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 a 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 aluminates, alkali metal silicates, 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 most preferred.

The sodium aluminate preferably has a solids content of 15 to 55%, preferably, Al₂O₃With Na₂The ratio of O is in the range of 0.5 to 1.55: 1.

In the next step in the manufacture of the detergent bar composition, detergent active may be added in the acid form or in the neutralised salt form. 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 with the carbonic acid, or simultaneously with the addition of the carbonic acid. In the above, a partially neutralized water-soluble carbonate may be used instead of carbonic acid.

The 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 ploughshare mixers, kneading elements with sigma type, multiple wiping overlap (multiwire overlap), simple curve or double arm mixers. The double arm kneading mixers may be of the splice or tangential design.

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

The formed dough is then preferably cooled by opening it to the atmosphere or passing it 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 milling soap or having an internal cooling mechanism. The retention time on the mill is preferably about 5 to 10 seconds, during which the temperature of the mixture is reduced to about 25 to 30 ℃.

The next step consists in extruding the dough, in which it is fed to a die press of conventional construction having a pair of contra-rotating worms in a single cooling cylinder equipped with a conical extrusion head, at the outlet of which is an extrusion die maintained at a temperature of 25 to 30 ℃. The die press has a common fixed perforated plate mounted with respect to the exit end of the worm screw at the inlet to the conical extrusion head so that the material is forced through the perforations of the plate, but the plate may be omitted. At a temperature of 25 to 30 ℃, the moulded material takes the form of a continuous rod with a rectangular cross section (7.6cm × 3.9cm, lying flat on its broad face) corresponding to a rectangular extrusion opening in the die.

The extruded rods were cut directly (e.g. 3 seconds after extrusion) to produce individual detergent bars having the same cross section as the rods, each 10cm long. Although the stick is flexible, it can be cut smoothly using a continuous vertical movement cutter without being significantly distorted by the action of the cutter blades.

Thereafter, preferably, the detergent bars are continuously passed through a holding conveyor belt maintained at a temperature of 15 to 20 ℃ (or if desired a cooling tunnel may be used). The strands are sufficiently stiff to be compressible (using a soap press in a well-known manner), wrapped in paper and packaged, or wrapped and packaged without compression. The bars are hard and strong both when freshly prepared and after curing, 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.

Examples

Example 1: preparation of structuring systems according to the invention

To prepare the structured system, 160 grams of a sodium aluminate solution containing a solids content of 45 wt% and water of about 55 wt% were placed in a plastic beaker. To the sodium aluminate solution, 200 g of sodium bicarbonate powder was slowly added, and the mixture was continuously stirred with a stainless steel spatula. In the early stages, after the addition of sodium bicarbonate, the mixture was a thin slurry that established rigidity after about 4 to 6 minutes. As the reaction progresses, the temperature of the mixture rises and the rigidity also increases to produce a structured system. The structuring system is in dry form, has a bound water content of about 10 to 45 wt.%, and comprises hydrated sodium carbonate and alumina hydroxide (hydrated aluminum material).

Bound water content was determined by thermogravimetric analysis: bound water content in the structured system was measured using a Parkin Elmer thermovirometric Analyzer TGA 8000. A defined amount of the prepared structuring system of example 1 was placed in the sample reservoir of the instrument and heated from 30 ℃ to 250 ℃ at a rate of 10 ℃/min. The sample weight was reduced due to water loss, the sample weight loss from 40 ℃ was recorded, and the amount of bound water content (% by weight) was determined.

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

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

Method I: for the preparation of a 100kg batch of high moisture detergent bars according to the invention, 31.05 wt% of a sodium aluminate solution containing 45 wt% solids content and the remaining 55 wt% water was placed in a sigma mixer. Next, 38% by weight 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 rose and the initial milky slurry gradually hardened to a rigid structured system.

To the resulting structuring system, 17.55% by weight of the acid precursor of LAS with a purity of 90% was added and mixing was continued for 5 minutes to completely neutralize the acid precursor of LAS. Thereafter, an inorganic filler (4% by weight of feldspar and 4% by weight of hydrous magnesium silicate) was added, and mixed for 2 to 4 minutes to form a uniform mass. To the homogeneous mass, calcium hydroxide and alkaline sodium silicate were added 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 keeping it open to the atmosphere or passing through a cold roll mill. Thereafter, the dough was passed through an extruder to form shaped bars and cut directly (e.g. 3 seconds after extrusion) to produce individual detergent bars having the same cross section as the bars, each 10.3cm long.

Although the stick is soft, it can be cut smoothly without being substantially distorted by the action of the cutter blades. The strips were hard and strong both freshly prepared and after curing, and had a smooth feel when used.

Method II:in an alternative process for the preparation of a detergent bar with a structuring system according to the invention, a 31.05 wt% sodium aluminate solution having a solids content of 45 wt% and a remaining 55 wt% water is placed in a sigma mixer. Next, 17.55 wt% of the acid precursor of LAS having a purity of 90% was added and mixing was continued for 5 minutes to completely neutralize the acid precursor of LAS. Thereafter, 38% by weight 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 rose and the initial milky slurry gradually hardened to 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 perfume, dye, colorant were added as described above and mixed for about 6 minutes to obtain an extrudable dough and made into detergent bars as detailed above.

Determination of penetration value:

the penetration value represents the hardness of the strip measured using a conical penetration gauge, and details of a typical instrument and measurement method are given below.

Conical needle meter

The manufacturer: adair Dutt & Company, Bombay

Measurement range: 0 to 40mm

Verification range: in 5 steps 20 measurement procedures: the entire mass resting on the test specimen (including the needle penetration into the test mass to a specified distance over a specified period of time, which is recorded to 0.1 mm) was allowed to fall freely over the test specimen. The average of at least 3 readings was taken and is provided in table 1 below.

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

TABLE 1

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

Feeling/grittiness:following the wash down protocol, a trained panel was used to assess grittiness by feel. The wash down protocol included holding the detergent bar under running water and evaluating the surface feel of the bar by rubbing the bar 40 times with a hand. The underwater smoothness of the strip when washed off was evaluated by trained panelists on a scale of 1 to 10, where 1 is moldy (mutty), 2 is sticky and slippery (skid), 3 is slippery (skid), 4 is very smooth (very smooth), 5 is smooth (smooth), 6 is slightly astringent (skid), 7 is astringent (draggy), 8 is slightly gritty (skid), 9 is very gritty/gritty (sand), and 10 is complete gritty (dump sand). Detergent bars of acceptable quality typically have a sensory score in the range of 7.8 to 8.

Abrasion/abrasion%:to determine the wear of the bars, the bars were taken at the initial weight. A single wash down protocol was followed in which the desized 100% textile cotton fabric was immersed in a bowl of water (water hardness 6FH Ca: Mg-2: 1). The fabric was then held in both hands and allowed to drain for 10 seconds. Thereafter, the fabric was laid flat in an enamel pan. The test strips were briefly immersed in 2.0L of water (6FH Ca: Mg 2:1) and the first side of the strip was rubbed 5 times along the length of the wet fabric so that there was no overlap in the rubbed areas. Thereafter, the wet web was turned over and the strip was rubbed 5 additional times along the length of the wet web using the same side of the strip. Re-placing the stripThe second side of the strip is then rubbed along the length of the second wet web in a similar operation to that performed on the first web. The weight loss after the above procedure was recorded and expressed as: a) weight loss in grams, and b)% loss by weight. The above experiments were performed in triplicate.

Water immersion (Sogginess):to evaluate the water immersion of the strips, the abrasion test protocol described above was followed. Thereafter, a trained panel of users evaluated the bars by feeling the first and second sides of the bars with four fingers and rating the wet on a scale of 0 to 8, where 0 is dry, 1 is wet (moist) but not sticky, 2 is wet (wet) but not sticky, 3 is slightly sticky, 4 is sticky, 5 is slightly pasty, 6 is pasty, 7 is wet, and 8 is very wet. The score provided is recorded.

Density:the density of the bars was measured by standard methods and calculated using the following formula:

TABLE 1a

Wear (gm loss/sheet)	118.55
		Wear out%	46.76
Top surface immersion in water-total	11.00
		Bottom surface immersion in water-total	10.00
Water immersion-bottom surface of last day	3.00
		Penetration value	2.00
Sense of gravel	8.00
		Appearance of the product	Absence of efflorescence
Density of bars (gm/cm)³)	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 the comparative detergent bar (composition a), 36 wt% of the acid precursor of LAS anionic surfactant was mixed with 25.75 wt% sodium carbonate in a sigma mixer to form a neutralized paste to which 10 wt% water and 28.1 wt% corn starch were added to form a dough. The dough is allowed to cool by keeping it open to the atmosphere. Once cooled, the dough was passed through an extruder and formed into shaped bars and cut directly (e.g. 3 seconds after extrusion) to produce individual detergent bars having the same cross section as the bars, each 10.3cm long. The final bar composition is provided in table 3.

For the preparation of a detergent bar according to the invention (example 3), a 30 wt% sodium aluminate solution containing 45 wt% solids content and 55 wt% water remaining was placed in a sigma mixer. Subsequently, 34% by weight 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 rose and the initial milky slurry gradually hardened to a rigid structured system. To the resulting structuring system 36% by weight of the acid precursor of LAS was added and mixing was continued for 5 minutes to fully neutralize the acid precursor of LAS and the resulting dough was allowed to cool by keeping it open to the atmosphere. Once cooled, the dough was passed through an extruder and formed into shaped bars and cut directly (e.g. 3 seconds after extrusion) to produce individual detergent bars having the same cross section as the bars, each 10.3cm long. The final bar composition is provided in table 3.

Measurement of Penetration Value (PV):

the penetration value represents the stiffness or hardness of the strip and is measured using a standard cone penetration meter (Petrotest PNR 10). To measure the penetration value, the needle point of the penetration meter was adjusted on the flat surface of the sample detergent bar so that it came into point contact with the surface. The adjustment was made precisely using a side lift-lit lamp, so that the shadow of the tip coincided with the tip itself. After the adjustment is completed, the scale is adjusted to zero and the instrument is turned on. The instrument measures the penetration depth of the needle at 5 second duration. The penetration value was recorded and the above process was repeated three times at different points on the surface of the strip.

And (3) measuring the moisture content:

the moisture content of the detergent bars was determined by powdering the bars, holding 1gm of the powder material on a plate of a hot air oven and heating to 130 ℃. The material was held for a period of 1 hour or until its weight was 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 calculation and is provided in table 1.

The moisture content, hardness of the bars were determined using the methods described above and the values recorded are presented in table 3.

TABLE 3

Composition (I)	Composition A (% by weight)	Example 3 (wt%)
			Sodium LAS	39.12	39.12
Sodium carbonate	21.28	27.89
			Alumina (Al)₂O₃)	0	9.43
Water (W)	11.5	23.56
			Corn starch	28.1	0
Total of	100	100
			Moisture content (% by weight)	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. The detergent bar composition according to the invention also retained a higher level of moisture while scoring higher in hardness than the detergent bar prepared according to the prior art (composition a).

Example 4: powder detergent compositions comprising structuring systems according to the invention

A spray-dried base powder having the composition as provided in table 4 was prepared. For the preparation of the comparative spray-dried powder detergent composition (composition B), a 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 invention (example 4), a defined amount of a structuring system prepared according to example 1 comprising a moisture content of 42 wt% was added to a spray-dried base powder prepared as given in table 4.

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

TABLE 4

The data shown in table 4 show that the composition with a structuring system prepared according to the invention (example 4) has a higher moisture content than the comparative detergent composition (composition B) and is still free flowing.

Claims

1. A process for preparing a structuring system in a detergent composition comprising a high moisture retaining structuring system comprising:

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

0.5 to 30 wt% 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 wt%,

the composition is a particulate, powder or granule composition comprising from 25 to 60% by weight of said structuring system,

and wherein the process comprises the step of contacting the carbonated or partially neutralized water soluble carbonate with a strong base, wherein the strong base is selected from an alkali metal aluminate or an alkali metal silicate.

2. The method of claim 1, wherein the strong base is aqueous sodium aluminate having a solids content in the range of 40 to 55 weight percent or sodium silicate in solid form having a moisture content of 4 to 35 weight percent.

3. The process of claim 1 or 2, wherein the partially neutralized, water soluble carbonate is a bicarbonate of an alkali metal.