CN1289650C - Improved detergent bar composition - Google Patents

Abstract

A detergent bar comprising a layered inorganic material for personal or fabric washing or hard surface cleaning. The detergent compositions have improved water retention capacity without affecting sensory and physical properties. A process for the preparation of the detergent bar composition is also provided.

Description

Improved bar detergent composition

The present invention relates to a synergistic bar soap/detergent composition for body or fabric washing or hard surface cleaning. In particular, the present invention relates to detergent bar compositions having improved water retention without compromising sensory and physical properties.

Conventional soap-based detergent bars for body washing contain more than about 70% by weight TFM, with the balance being water (about 10-20%) and other components such as colorants, fragrances, preservatives, etc. wait. Small amounts of structurants and fillers are also present in this composition, which replace some of the soap in the bar while maintaining the desired firmness of the bar. Several known fillers include starch, kaolin and talc.

Non-abrasive hard soaps containing less than 35% moisture are also available. The TFM of this soap bar is about 30-65%. TFM can be reduced by using insoluble particulate material and/or soluble silicates.

Milled soap bars typically have a water content of about 8-15%, while non-milled hard soap bars typically have a water content of about 20-35%.

Fabric washing compositions contain as an essential ingredient a surfactant system which acts to aid in the removal of soils from fabrics and their wash liquor suspensions. Detergent bars are required to have acceptable physical strength so that they retain their structural integrity during handling, shipping and use. The hardness of the strip is a particularly important property both during and after its manufacture. The water content in detergent bars is generally maintained at around 6%. The binders and fillers used in NSD bars are generally ores, which exhibit wide variability in quality, usually due to different mining. Increasing and maintaining the water content in the bar is particularly beneficial for producing bars of larger size, which enhances consumer appeal. Commercially available detergent bars contain detergent active ingredients and detergency builders, fillers, structurants, hardeners and optional ingredients such as abrasives, perfumes, colorants and bleaches.

Commercially available hard surface cleaning compositions typically include one or more surfactants with a large amount of abrasive dispersed therein. Combinations of these components and dielectrics are generally used to form suspension systems well known in the art.

Inorganic particles form an essential component in detergent formulations for personal washing, fabric and especially many hard surface cleaning compositions. Commonly used inorganic particles are calcite, dolomite, feldspar, silica, silicates, other carbonates, bicarbonates, borates, sulfates

Hydroxycarbonates of alkaline earth metals and layered double hydroxides of one or more alkaline earth metals and aluminum are also known to exist in their mineral form, but are not commonly used in soaps and detergents. Hydroxycarbonates of alkaline earth metals as flow aids, ceramic precursors, refractory materials, and layered double hydroxides of one or more alkaline earth metals and aluminum as catalyst precursors, adsorbents, antacids .

EP557089 (Unilever, 1993), WO9616634 (Unilever, 1996) disclose the use of layered double hydroxides in ceramic compositions for enhanced release of benefit agents.

WO 96/25913 discloses the use of monophasic zinc hydroxycarbonate as an antimicrobial agent in body care products, especially products containing soap or synthetic detergents. This is limited to making zinc ions, which are known to provide antimicrobial properties without affecting the product itself.

WO94/03574 and WO95/21234 relate to the use of double hydroxide materials such as hydrotalcites in machine dishwashing compositions. WO 89/08693 describes the use of crystalline mixed metal hydroxides as thickeners or viscosity modifiers.

It has now been found that the use of such layered inorganic materials in detergent formulations can improve water retention in bars without compromising other physical and sensory properties. Can also be combined with other liquid benefit agents in the bar.

According to the present invention there is provided an improved detergent bar composition comprising:

-10-80% detergent actives

- 1-30% layered inorganic materials having the general formula:

(M ²⁺ ) ₁ (N ³⁺ ) _a (OH ^-1 ) _b (A ^-c ) _d eH ₂ O wherein M ²⁺ = one or more positive divalent metal ions;

N ³⁺ = positive trivalent metal ion and 'a' ranges from 0-1;

OH ^-1 = hydroxyl, and 'b' ranges from 0.1 to 4;

A ^-c ='c' refers to the valence of the inner layer anion 'A' and the range of 'd' is 0-1;

H ₂ O = water of crystallization, where 'e' ranges from 0-10;

wherein charge neutrality is maintained (ie 2+3a-(b+cd)=0);

- 12-52% water or other liquid benefit agent;

and optionally other conventional ingredients.

Particularly preferred positive divalent metal ions may be magnesium, calcium and/or zinc, and positive trivalent metal ions are aluminium. Anions can be negative monovalent such as chloride or nitrate, or negative divalent such as carbonate or sulfate or tetraborate, or negative trivalent such as phosphate or borate.

According to a preferred aspect of the present invention there is provided an improved detergent bar composition comprising:

- 10-80% detergent active substances;

- 1-30% of inorganic materials having the following general formula:

(M ²⁺ ) ₁ (OH ⁻¹ ) _b (A ^−c ) _d eH ₂ O where M ²⁺ = positive divalent metal ion is magnesium;

OH ^-1 = hydroxyl, and 'b' is 0.2-0.8;

A ^-c = anion is carbonate and 'd' is 0.6-0.9;

H ₂ O = water of crystallization, where 'e' is 1-5;

wherein charge neutrality is maintained (ie 2-(b+cd)=0);

- 12-52% water or other liquid benefit agent;

and optionally other conventional ingredients.

According to another aspect of the present invention there is provided a process for preparing an improved detergent bar composition comprising 10-80% detergent active of which 1-30% is a layered inorganic material having the general formula :

(M ²⁺ ) ₁ (N ³⁺ ) _a (OH ^-1 ) _b (A ^-c ) _d eH ₂ O wherein M ²⁺ = one or more positive divalent metal ions;

N ³⁺ = positive trivalent metal ion and 'a' ranges from 0-1;

OH ^-1 = hydroxyl, and 'b' ranges from 0.1 to 4;

A ^-c ='c' refers to the valence of the inner layer anion 'A' and the range of 'd' is 0-1;

H ₂ O = water of crystallization, where 'e' ranges from 0-10;

wherein charge neutrality is maintained (ie 2+3a-(b+cd)=0);

- 12-52% water or other liquid benefit agent;

- and optionally other conventional components;

Wherein said layered inorganic material is produced in situ by mixing mixed metal oxide precursors with a soap substance in the presence of water at a temperature in the range of 20-80°C.

Mixed metal oxide precursors can be obtained by calcining the corresponding layered double hydroxides in the temperature range of 450–550 °C.

An essential feature of the present invention is the addition of certain layered inorganic alkaline salts such as hydroxycarbonates and layered double hydroxides to soaps and detergents, which help to improve the water structure and thus improve the water structure during storage and use. Medium preserves the structured water in the bar.

Many natural and synthetic layered double hydroxides are known with various metal cations, where the divalent cation is magnesium, manganese, iron, cobalt, nickel, copper, zinc or calcium and the trivalent cation is aluminum, chromium, Manganese, Iron, Cobalt, Nickel and Lanthanum. Particularly preferably, the positive divalent metal ion may be magnesium, calcium and/or zinc, the positive trivalent metal ion is aluminum, and the anion may be negative monovalent such as chloride or nitrate, or negative divalent such as carbonate or sulfuric acid salt or tetraborate, or a negative trivalent such as phosphate or borate.

The layered inorganic materials used in the composition can be obtained commercially or prepared separately. The layered double hydroxide can be added to the tallow soap prior to spray drying of the soap or added to the dried soap bar. Alternatively, layered double hydroxides can also be generated in situ from their corresponding mixed metal oxide precursors. Mixed metal oxide precursors can be obtained by calcining the corresponding layered double hydroxides in the temperature range of 450–550 °C. Mixed metal oxide precursors can be added to tallow soap prior to spray drying of the soap or to deformed dry soap bars to give layered double hydroxides. Certain layered inorganic materials can also be obtained from nature, such as ores.

Layered inorganic materials, i.e., hydroxycarbonates or layered double hydroxides, can be prepared by combining an aqueous solution of an appropriate stoichiometric metal salt/metal salt blend with an aqueous sodium carbonate solution, typically at elevated temperatures of 80-90°C thing. Filter and wash the precipitate containing layered inorganic material thoroughly with copious amounts of water to remove all soluble electrolyte. The resulting wet cake was dried overnight in an oven at 130°C. Such materials suitable for use in detergent compositions are generally white powders having an average particle size in the range of 5-12 microns. In the case of larger particle sizes, the material is ground to achieve the desired particle size.

Examples of layered materials are hydromagnesite, hydrotalcites containing carbonates, nitrates, sulfates, tetraborates as their inner layer anions.

The detergent actives can be soap or non-soap surfactants. In certain embodiments, the composition is a foaming bar; it may preferably contain some soap, preferably at least 5% by weight of the bar. In other embodiments it is preferred to contain at least 2%, preferably at least 5% by weight of synthetic or non-soap anionic surfactant.

The term soap means carboxy fatty acid salts. Soap can be derived from any triglyceride commonly used in soap making, therefore, the carboxylate anion in soap can contain 8-22 carbon atoms.

Soaps are obtained by saponifying fats and/or fatty acids using suitable alkaline substances containing sodium, potassium, aluminum or mixtures thereof. Saponification can also be carried out by reacting a precursor of one or more detergent actives with _an alkaline material containing such as sodium aluminate having a solids content of 20-55% where _Al2O3 The weight ratio to _Na2O is 0.5-1.55, and one or more carboxylic acids having an equivalent weight of less than 150 may or may not be present. The carboxylic acid may be selected from non-fatty acid aliphatic monocarboxylic acids and polymers thereof, more preferably they are C ₁ -C ₅ carboxylic acids and polymers thereof. Further suitable carboxylic acids are aliphatic or aromatic di-, tri- or polycarboxylic acids, and also hydroxy- and aminocarboxylic acids.

Fats or oils commonly used in soap making may be such as tallow, tallow, palm oil, palm stearin, soybean oil, fish oil, castor oil, rice bran oil, sunflower oil, coconut oil, carnauba kernel oil, Palm seed oil and others. In the above method, the fatty acid is derived from oils/fats of coconut, rice stick, peanut, tallow, palm, palm seed, cotton seed, soybean, castor, etc. Fatty acid soaps can also be produced artificially (eg by oxidation of petroleum or hydrogenation of carbon monoxide by the Fischer-Tropsch method). Resin acids such as those present in tall oil may be used. Naphthenic acids may also be used.

Tallow fatty acids can be derived from various animal sources and generally contain about 1-8% myristic acid, about 21-32% palmitic acid, about 14-31% stearic acid, about 0-4% palmitoleic acid , about 36-50% oleic acid and about 0-5% linoleic acid. The general distribution is 2.5% myristic acid, 29% palmitic acid, 23% stearic acid, 2% palmitoleic acid, 41.5% oleic acid and 3% linoleic acid. Other blends with similar distributions may also be included, such as blends derived from palm oil, derived from various tallows and lard.

Coconut oil means having a carbon chain length distribution of approximately 8% C ₈ , 7% C ₁₀ , 48% C ₁₂ , 17% C ₁₄ , 8% C ₁₆ , 2% C ₁₈ , 7% oleic acid and 2% linoleic acid fatty acid mixture (the first 6 fatty acids listed are saturated). Other sources with a similar carbon chain length distribution, such as palm or carnauba kernel oil, are also included in the term coconut oil.

The non-soap surfactants can be anionic, nonionic, cationic, amphoteric or zwitterionic, or mixtures thereof.

Suitable anionic detergent-active compounds are reaction products of water-soluble organic sulphates comprising in their molecular structure an alkyl group having from 8 to 22 carbon atoms and a group selected from sulphonic acid or sulphate groups and mixtures thereof.

Examples of suitable anionic detergents are: sodium and potassium alcohol sulfates, especially those resulting from the sulfation of higher alcohols formed by the reduction of glycerides of tallow or coconut oil; sodium alkylbenzene sulfonates and Potassium, such as those alkylbenzenesulfonates in which the alkyl group contains 9-15 carbon atoms; sodium alkylglyceryl ether sulfates, especially ethers of higher alcohols from tallow and coconut oil; coconut fatty acid monoglycerol Sodium ester sulfate; sodium and potassium salts of sulfate esters derived from the reaction product of 1 mole of higher aliphatic alcohols with 1-6 moles of ethylene oxide; sodium and potassium salts of alkylphenol oxirane ether sulfates containing 1-8 units of oxirane molecules with an alkyl group containing 4-14 carbon atoms; and reaction products of isethionated fatty acids, such as those derived from coconut oil and its mixture.

Preferred water-soluble synthetic anionic detergent-active compounds are alkali metal salts (such as sodium and potassium) and alkaline earth metal salts (such as calcium and magnesium) of higher alkylbenzenesulfonic acids and their combinations with olefin sulfonates and higher alkyl sulfates, and a mixture of higher fatty acid monoglyceride sulfates. The most preferred anionic detergent-active compounds are higher alkyl aromatic hydrocarbon sulfonates, such as higher alkylbenzene sulfonates containing 6 to 20 carbon atoms in the linear or branched alkyl group, wherein particular embodiments include higher Sodium salt of alkylbenzenesulfonic acid or higher alkyltoluene, xylene or phenolsulfonic acid, sodium alkylnaphthalenesulfonate, ammonium dipentylnaphthalenesulfonate and sodium dinonylnaphthalenesulfonate.

Suitable nonionic detergent-active compounds can be broadly described as compounds obtained by condensation of an inherently hydrophilic oxyalkylene group with an organic hydrophobic compound which may itself be aliphatic or alkylaromatic. The length of the hydrophilic or polyoxyalkylene groups condensed with any particular hydrophobic group can be conveniently adjusted to obtain a water-soluble compound having the desired degree of balance between hydrophilicity and hydrophobicity.

Specific examples include condensation products of aliphatic alcohols containing 8 to 22 carbon atoms and ethylene oxide in a linear or branched configuration, such as coconut oil containing 2 to 15 moles of ethylene oxide per mole of coconut alcohol Condensates of ethylene oxide; condensates of alkylphenols, the alkyl group of which contains 6-12 carbon atoms, containing 5-25 moles of ethylene oxide per mole of alkylphenol; reaction products of ethylenediamine and propylene oxide with Condensates of ethylene oxide containing 40-80% by weight of polyoxyethylene groups and having a molecular weight of 5,000-11,000; tertiary amine oxides with the structure _R3NO , wherein one group R is 8-18 Alkyl groups of carbon atoms, others are methyl, ethyl or hydroxyethyl groups, such as dimethyl dodecylamine oxide; tertiary phosphine oxides with the structure R ₃ PO, one of the groups R is 10- An alkyl group with 18 carbon atoms, other alkyl groups or hydroxyalkyl groups with 1-3 carbon atoms, such as dimethyl dodecyl phosphine oxide; and dialkyl sulfoxides with the structure R ₂ SO, wherein The group R is an alkyl group of 10-18 carbon atoms, the other is a methyl or ethyl group, such as methyl tetradecyl sulfoxide; fatty acid alkanolamides; oxidation of fatty acid alkanolamides and alkylthiols Alkene condensates.

Amphoteric, cationic or zwitterionic detergent actives may also be included in the compositions according to the invention.

Such strips are prepared by conventional methods, such as frame cooling or extrusion (molding). Typically, in the extrusion process, the fatty acids are neutralized with base as described above or in the presence of non-soap detergent actives/minor optional additives and dried to the desired moisture content. The dried soap is then mixed with the rest of the micro-additives/non-soap detergent in the mixer, machined in a three-roll mill and molded into blocks under vacuum shape. The blocks are then punched into bars.

Other optional ingredients such as fillers, colorants, fragrances, sunscreens, preservatives, one or more water-soluble/water-insoluble particulate materials such as talc, alumina, borax, kaolin, polysaccharides, liquid benefit agents such as sunscreens , moisturizers, emollients, anti-aging compounds, hair conditioners and other conventional ingredients can be added to the composition.

The soaps/detergent bars of the present invention exhibit excellent visuals, hand, firmness, cleanliness and lather.

Some illustrative, non-limiting examples are provided here, showing comparative results for compositions within and outside the scope of the invention.

Example

The preparation method of i Hydroxy Magnesium Carbonate

Under constant stirring conditions, carefully add 100 mL of 1 molar magnesium sulfate solution dropwise to an equal volume of 1 molar sodium carbonate solution over 30 minutes. After the reaction, the slurry was filtered through Whatman 1 filter paper. The precipitate was washed with hot water to remove sodium sulfate and dried at 110°C until the moisture content was below 3%. The resulting precipitate of magnesium hydroxycarbonate was characterized using powder pattern X-ray diffraction, and the same method was used to characterize the preparation of the soap bars described below.

ii Method of preparing soap bar

Soap bars having the formulations described in Table 1 were prepared using the following procedure.

The bars were placed in a sigma mixer and inorganic materials such as talc (Examples 1 and 2), and layered inorganic materials such as magnesium hydroxycarbonate (Examples 3 and 4) were added to the comparative formulations. Magnesium hydroxide was added in Example 5 and magnesium carbonate was added in Example 6. The mass was mixed thoroughly for about 10 minutes, then processed conventionally by grinding and molding in a two-stage plodder, followed by punching and packaging.

The following procedure was used to test the hardness and water retention of the samples prepared as described above after storage under hot and dry conditions (45° C. and 40-70 relative humidity).

ii Determination of hardness: penetration value (PV)

At 37°C, use a cone-type penetrometer to measure the penetration value of the indicator bar hardness; the general instrument and its measurement method are described in detail below.

cone penetrometer

Manufacturer: Adair Dutt & Company, Bombay.

Measuring range: 0-40 mm

Correction range: 20, step size is 5

Measurement procedure: Allow the entire substance (including the penetrometer needle and the standard weight) just above the test sample to fall freely, so that it penetrates the tested substance to a certain distance within a certain period of time, and read this distance, accurate to 1/10 mm. Then repeat the operation at least 3 times and take the average value.

iv. Water retention:

The initial wetness in the bar was determined using the infrared balance hereinafter. Packaged bar samples were initially weighed and stored for 3 months under heat and dry (HD) conditions maintaining a temperature of 45°C and a relative humidity of 40-70%. Weigh the samples periodically and record the data at the end of 3 months. Calculate the moisture % and weight % loss of the bar.

Table 1 Composition weight % Example 1 Example 2 Example 3 Example 4 Example 5* Example 6 Soap 72 68.7 77.4 68.7 77.4 77.4 soda ash 0.9 0.9 0.9 0.9 0.9 0.9 humidity 15.1 19.0 14.8 19.0 14.8 14.8 talc 10 10 - - - - Magnesium Hydroxycarbonate - - 5 10 - - magnesium hydroxide - - - - 5 - magnesium carbonate - - - - - 5 Minor component 2 1.4 1.9 1.4 1.9 1.9 product nature Penetration (PV.) 39 41 35 32 - 37 Humidity % after storage at 45°C for 3 months 6.1 6.9 9.1 10.0 - 6.0 Weight % loss after storage 9.7 13.0 6.3 10.0 - 9.5

Hair strips are highly alkaline and not suitable for use.

The data in Table 1 show that physical properties such as hardness and processability of bars with high moisture content can be significantly improved by using magnesium hydroxycarbonate compared to talc. The water retention capacity of the bar incorporating the layered inorganic material was higher compared to the control formula containing talc.

Processing bars containing magnesium hydroxide is not possible because it creates a very high alkalinity in the bars and is generally not suitable for use in soaps. However, magnesium hydroxide or magnesium carbonate does not provide the moisturizing power of the bar due to the use of magnesium hydroxycarbonate. The use of magnesium hydroxycarbonate did not affect the organoleptic properties of the bar such as feel, lather, etc., as documented in the internal register.

Claims (7)

1. A detergent bar composition comprising: (i) 10-80% detergent active agent; (ii) 1-30% layered organic material having the following general formula: (M ²⁺ ) ₁ (OH ^-1 ) _b (A ^-c ) _d eH ₂ O where M ²⁺ is magnesium OH = hydroxyl group A is carbonate H ₂ O = water of crystallization b is 0.2-0.8 c = refers to the valency of the anion A d is 0.6-0.9 e is 1-5, and which maintains charge neutrality, (iii) 12-52% water or other liquid benefit agent; and (iv) Other conventional ingredients. 2. A composition according to claim 1 above wherein the customary ingredients are selected from fillers, colourants, fragrances, opacifiers, preservatives, water soluble/insoluble particulate materials or liquid benefit agents. 3. A composition according to claim 1 above, wherein the composition in stick form is a foaming composition in stick form. 4. A composition according to any one of the preceding claims 1-3, wherein the bar composition contains soap. 5. A composition according to claim 4, wherein the composition contains at least 5% soap. 6. A composition according to any one of the preceding claims 1-3, wherein the bar composition contains at least 2% synthetic or non-soap anionic surfactant. 7. According to the preparation method of the bar detergent composition of claim 1, comprising: In the temperature range of 20-80 °C, in the presence of water, the layered inorganic material is produced in situ by mixing the mixed metal oxide precursor with the soap material, wherein the mixed metal oxide precursor is passed through at 450 It is obtained by calcining the corresponding layered double hydroxide in the temperature range of -550°C.