WO2000042159A1

WO2000042159A1 - Detergent bar composition

Info

Publication number: WO2000042159A1
Application number: PCT/EP1999/010286
Authority: WO
Inventors: Vedantam Venkateswara Kumar; Fakhruddin Esmail Pacha
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Lever Ltd
Priority date: 1999-01-18
Filing date: 1999-12-20
Publication date: 2000-07-20
Also published as: IN192111B; AU3042300A

Abstract

The invention relates to a synergistic detergent bar composition for cleaning fabric or hard surfaces or for personal wash with up to 5 % soap.

Description

DETERGENT BAR COMPOSITION

Technical field

The invention relates to a synergistic detergent bar composition for cleaning fabric or hard surfaces or for personal wash. More particularly the compositions of the invention are especially, but not exclusively, useful for cleaning fabric.

Background and Prior art

Fabric washing compositions contain, as an essential ingredient, a surfactant system whose role is to assist in removal of soil from the fabric and its suspension in the wash liquor. Other important components are the detergent builders together with optional components for example abrasives, fillers, perfumes, alkaline salts and bleaching agents.

Commercial hard surface cleaning compositions typically comprise, one or more surfactants and a plurality of abrasives dispersed therein. Combinations of these together with electrolytes are generally used to form a suspending system as is well known in the art.

Sensorial attributes such as bar feel, lather, soapiness, ease of application, bar hardness and detergency are important factors to be considered while formulating detergent bar compositions. It has been found that detergent bars having linear alkyl benzene sulphonate as the active and with high level of fillers exhibit poor sensorial properties thereby leading to poor economy. It has further observed that these bars undergo a gradual deterioration in physical properties on storage and the excessive bar hardening is especially significant which leads to poor performance of such bars.

Foam volume and foam stability are often used to gauge the cleaning efficiency and it has been found to be desirable to formulate a detergent composition with improved foaming performance. It is also important to see that this aspect is not affected due to storage of the product.

Detergent formulations comprising a mix of non-soap surfactants and soap ranging from 10 to 70% is reported in prior art to obtain various benefits (BR8905607; WO9805752; WO9742283).

WO 98/16611 (Procter & Gamble) discloses a laundry bar composition comprising up to 10% soap and an anionic surfactant wherein at least 20% of the surfactant is essentially alkyl sulphate. This prior art solves the problem of brittleness of the bar caused by the addition of certain surfactants especially alkyl sulphate by the incorporation of dihydric alcohol in the formulation.

GB2181739 (Unilever) discloses the incorporation of soap and anionic surfactant in a ratio of more than 1 :2 to improve the rate of lather generation. We have found that the presence of up to 5% soap in detergent compositions based on non-soap detergent (NSD) active effectively enhances foam and foam stability, improve detergency, and maintenance of physical properties on storage.

According to the present invention there is provided a synergistic detergent bar composition comprising 0.1 to 5% soap, 5-40% non-soap detergent active component said bar being essentially free of dihydric alcohol. The detergent composition of the invention has properties of improved cleaning during use and also enhance the foam volume and its stability. The conventional NSD bars generally undergo a gradual deterioration in physical properties and sensorial attributes due to storage leading to poor economy. It is found that Incorporation of small amounts of soap to non-soap detergent active enables to deliver the good properties of the non-soap active without deterioration of its properties under storage conditions. Zeolite may be optionally incorporated at levels of from 0 wt% up to 15 wt%, preferably up to 10 wt%, most preferably up to 8 wt%.

Soap

The term soap denotes salts of carboxylic fatty acids. The soap may be derived from any of the triglycerides conventionally used in soap manufacture - consequently the carboxylate anions in the soap may contain from 8 to 22 carbon atoms.

For a soap having 18 carbon atoms, an accompanying sodium cation will generally amount to about 8% by weight. Other cations may be employed as desired for example zinc, potassium, alkyl ammonium and aluminium.

The soap may be obtained by saponifying a fat and/or a fatty acid. The preferred triglyceride may be fats or oils generally used in soap manufacture and includes tallow, tallow stearines, palm oil, palm stearines, soya bean oil, fish oil, caster oil, rice bran oil, sunflower oil, coconut oil, babassu oil, palm kernel oil, and others. In the above process the fatty acids are derived from oils/fats selected from coconut, rice bran, groundnut, tallow, palm, palm kernel, cotton seed, soybean, castor etc. The fatty acid soaps can also be synthetically prepared (e.g. by the oxidation of petroleum or by the hydrogenation of carbon monoxide by the Fischer-Tropsch process). Resin acids, such as those present in tall oil, may be used. Naphthenic acids are also suitable. Particularly useful tallow fatty acids can be derived from various animal sources and generally comprise 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. A typical distribution is 2.5% myristic acid, 29% palmitic acid, 23% stearic acid, 2% palmitoleic acid, 41.5% oleic acid, and 3% linoleic acid. Other mixtures with similar distribution, such as those from palm oil and those derived from various animal tallow and lard are also included.

Coconut oil refers to fatty acid mixtures having an approximate carbon chain length distribution of 8% C₈, 7% C₁₀, 48% C₁₂, 17% C , 8% Cι₆, 2% C₁₈, 7% oleic and 2% linoleic acids (the first six fatty acids listed being saturated). Other sources having similar carbon chain length distributions, such as palm kernel oil and babassu kernel oil, are included within the term coconut oil.

The alkali selected to effect the neutralisation may be in any convenient form. Preferably it comprises an aqueous solution. Suitable alkalis include alkali metal and alkaline earth metal hydroxides and carbonates. Two preferred alkalis are sodium hydroxide and sodium carbonate. Non-soap detergent

The composition according to the invention will preferably comprise a detergent active which is generally chosen from an anionic, nonionic, cationic, zwitterionic detergent active or mixtures thereof. 5

Especially suitable anionic detergent active compounds are water soluble salts of organic sulphuric reaction products having in the molecular structure an alkyl radical containing from 8 to 22 carbon atoms, and a radical chosen from sulphonic acid or sulphur acid ester radicals and mixtures thereof.

10

Examples of preferred anionic detergents are sodium and potassium alcohol sulphates, especially those obtained by sulphating the higher alcohols produced by reducing the glycerides of tallow or coconut oil; sodium and potassium alkyl benzene sulphonates such as those in which the alkyl group contains from 9 to

15 15 carbon atoms; sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyce de sulphates; sodium and potassium salts of sulphuric acid esters of the reaction product of one mole of a higher fatty alcohol and from 1 to 6 moles of ethylene oxide; sodium and potassium salts of alkyl phenol

20 ethylene oxide ether sulphate with from 1 to 8 units of ethylene oxide molecule and in which the alkyl radicals contain from 4 to 14 carbon atoms; the reaction product of fatty acids esterified with isethionic acid and neutralised with sodium hydroxide where, for example, the fatty acids are derived from coconut oil and mixtures thereof.

The preferred water-soluble synthetic anionic detergent active compounds are selected from the group including the alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of higher alkyl benzene sulphonates, olefin sulphonates, higher alkyl sulphates, the higher fatty acid monoglyceride sulphates and mixtures thereof. The most preferred anionic detergent active compounds are higher alkyl aromatic sulphonates such as higher alkyl benzene sulphonates containing from 6 to 20 carbon atoms in the alkyl group in a straight or branched chain, particular examples of which are sodium salts of higher alkyl benzene sulphonates or of higher-alkyl toluene, xylene or phenol sulphonates, alpha olefin sulphonates, alkyl naphthalene sulphonates, ammonium diamyl naphthalene sulphonate, sodium dinonyl naphthalene sulphonate and mixtures thereof. Particularly preferred anionic detergent active compounds are sodium salts of higher alkyl benzene sulphonates, alpha olefin sulphonates and mixtures thereof.

Suitable nonionic detergent active compounds can be broadly described as compounds produced by the condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic or polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.

Particular examples include the condensation product of aliphatic alcohols having from 8 to 22 carbon atoms in either straight or branched chain configuration with ethylene oxide, such as a coconut oil ethylene oxide condensate having from 2 to 15 moles of ethylene oxide per mole of coconut alcohol; condensates of alkylphenols whose alkyl group contains from 6 to 12 carbon atoms with 5 to 25 moles of ethylene oxide per mole of alkylphenol; condensates of the reaction product of ethylenediamine and propylene oxide with ethylene oxide, the condensate containing from 40 to 80% of polyoxyethylene radicals by weight and having a molecular weight of from 5,000 to 11 ,000; tertiary amine oxides of structure R₃NO, where one group R is an alkyl group of 8 to 18 carbon atoms and the others are each methyl, ethyl or hydroxyethyl groups, for instance dimethyldodecylamine oxide; tertiary phosphine oxides of structure R₃PO, where one group R is an alkyl group of from 10 to 18 carbon atoms, and the others are each alkyl or hydroxyalkyl groups of 1 to 3 carbon atoms, for instance dimethyldodecylphosphine oxide; and dialkyl sulphoxides of structure R₂SO where the group R is an alkyl group of from 10 to 18 carbon atoms and the other is methyl or ethyl, for instance methyltetradecyl sulphoxide; fatty acid alkylolamides; alkylene oxide condensates of fatty acid alkylolamides and alkyl mercaptans.

Suitable amphoteric detergent-active compounds that optionally can be employed are derivatives of aliphatic secondary and tertiary amines containing an alkyl group of 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for instance sodium 3-dodecylamino- propionate, sodium 3-dodecylaminopropane sulphonate and sodium N-2- hydroxydodecyl-N-methyltaurate. Suitable cationic detergent-active compounds are quaternary ammonium salts having an aliphatic radical of from 8 to 18 carbon atoms, for instance cetyltrimethyl ammonium bromide.

Suitable zwitterionic detergent-active compounds that optionally can be employed are derivatives of aliphatic quaternary ammonium, sulphonium and phosphonium compounds having an aliphatic radical of from 8 to 18 carbon atoms and an aliphatic radical substituted by an anionic water-solubilizing group, for instance 3-(N-N-dimethyl-N-hexadecylammonium) propane-1- sulphonate betaine, 3-(dodecylmethyl sulphonium) propane-1 -sulphonate betaine and 3-(cetylmethylphosphonium) ethane sulphonate betaine.

Further examples of suitable detergent-active compounds are compounds commonly used as surface-active agents given in the well-known textbooks "Surface Active Agents", Volume I by Schwartz and Perry and "Surface Active Agents and Detergents", Volume II by Schwartz, Perry and Berch.

The non-soap detergent active is preferably anionic and the total amount of non-soap detergent active compound to be employed in the detergent composition of the invention will preferably be from 10 to 30% and more preferably from 10 to 25% by weight.

For generating the mixture of soap and anionic detergent any of the following routes may be employed. i. The fatty acids may be co-neutralised with the synthetic anionic surfactant. ii. The synthetic anionic surfactant is neutralised in presence of soap. iii. The fatty acids are neutralised in presence of readily neutralised synthetic anionic surfactant. iv. Neutralised synthetic surfactant is blended with soap

The preferable route being blending of neutralised synthetic surfactant is with soap. Builders

The detergency builders used in the formulation are preferably inorganic and suitable builders include, for example, alkali metal aluminosilicates (zeolites), alkali metal carbonate, sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), citrates, sodium nitrilotriacetate (NTA) and combinations of these. Builders are suitably used in an amount ranging from 1 to 50% by wt, preferably from 1 to 30% by wt. Zeolite if used as builder is present at levels not exceeding

10% by wt.

Abrasives

A particulate abrasive phase is a useful ingredient of compositions according to the present invention.

Preferably, the particulate phase comprises a particulate abrasive which is insoluble in water. In the alternative, the abrasive may be soluble and present in such excess to any water present in the composition that the solubility of the abrasive in the aqueous phase is exceeded and consequently solid abrasive exists in the composition.

Preferred levels of abrasive range from 15-45 wt%, more preferably in the range 20-40 wt%. The physical form of the product will be influenced by the level of abrasive present. The most preferred abrasives are mixtures of calcium and magnesium carbonates (as dolomite), potassium sulphate, alumina, hydrated alumina, feldspars, talc and silica.

Other Ingredients

Other ingredients such as structurants for e.g. alumino-silicate formed in situ as described in our GB patent 2099013 or added externally, perfumes, colouring agents, polymers, fluoresces, enzymes, bleaches can also be used in the formulation, for example, in an amount up to 10 wt%.

Fillers

Fillers suitable for use in the formulation include kaolin, calcium carbonate (calcite), soapstone, china clay and the like, used singly or in combination, suitably in an amount ranging from 10 to 75% by weight, preferably from 30 to 70 wt%.

The following examples are intended to further illustrate the invention and are not intended to limit the invention in any way:

All percentages, unless indicated otherwise, are intended to be percentages by weight.

All numerical ranges in this specification and claims are intended to be modified by the term about. Finally, where the term comprising is used in the specification or claims, it is not intended to exclude any terms, steps or features not specifically recited.

Examples

Examples 1 and 2.

Process for preparation of the composition:

The formulations disclosed in Table 1 were prepared using conventional bar processing technology. The ingredients were mixed in a sigma mixer, extruded into bars and then cut into billets and stamped. In the experimental sample the soap was incorporated.

Table 1

l_AS = linear alkyl benzene sulphonate AOS = alpha olefin sulphonate ^* comprise china clay, calcite, dolomite and salts Example 3.

The bars prepared according to the invention and the control without the addition of soap was tested for different physical and sensorial attributes following the procedures described below.

Moisture Content of the bars.

The moisture content of the bars with formulations as in Example 1 and 2 was determined using freshly prepared bars and after a period of storage for 6 weeks. The moisture determination was done using a moisture balance which determines the % weight loss from the sample at 105°C.

Bar Hardness:

Bar hardness was determined using a penetrometer method. The penetrometer used was a SUR type PNR 8 (Sommer und Runge of Berlin DBR). The penetration needle had a point angle of 9°10 and was forced into the plane bar surface under a pressure of 100g for 10 seconds. The depth of penetration was measured in millimetres (mm); The hardness of the bar was measured after 1 week and 6 week storage. Assessment by an expert Panel:

Sensorial attributes and cleaning performance of detergent bars was evaluated by an expert panel after using the bars for 6 days, who score on a ten point scale. The bars of Example 1 and 2 stored for 8 weeks were evaluated.

The data presented in Table 2 shows that the moisture loss and increase in hardness of the bar is significantly reduced in the bars prepared according to the invention where there was an incorporation of 1 % soap in the formulation.

The scores given by the expert panel presented in Table 3 shows that effort required, wear, grit are reduced and the sensorial attributes such as lather, feel are superior. In addition the detergency and softness of the washed fabric is improved.

Table 2. Effect of storage on Moisture Content and Hardness of bars.

Table 3. Sensorial attributes by the Expert Panel

The above Table-3 shows that values marked ^* are significant at 99% and the one marked as 'ns' is not significant.

Incorporation of soap into NSD bars effectively enhances the sensorial attributes and maintenance of physical properties on storage.

Effect of Soap and Zeolite levels on the bar properties:

The formulations disclosed in Table 4 were prepared using conventional bar processing technology. The ingredients were mixed in a sigma mixer, extruded into bars and then cut into billets and stamped. In the experimental samples the soap level was maintained at 1% level and the zeolite level at 10% and were compared with soap and zeolite levels that were beyond the scope of the invention. Table 4

LAS = linear alkyl benzene sulphonate AOS = alpha olefin sulphonate *comprise china clay, calcite, dolomite and salts

The above mentioned samples were tested for different in use properties such as mush, rate of wear, sog, soil lather and bar hardness.

Mush: Refers to the paste like layer formed on the bar surface upon contact with water and is estimated by measuring the amount of bar loss/unit area.

Rate of wear: Refers to the amount of the bar loss during use which is measured by its weight.

Sog: Refers to the ingress of water from the atmosphere into the bar and relates to the cause of sogginess of the bar. This is measured by determining the bar hardness using a penetrometer by the procedure described earlier.

Soil lather: Refers to foam generated during wash by which the consumer controls the product dosage.

Bar hardness: Refers to the hardness of the bar after manufacture which gives an indication of the processability, strength and retention of structural integrity during handling, transport and use. This was measured by the procedure described earlier.

Table 5

^* The bars are soft for direct line packing. ^** Bars are hard and brittle.

The data presented in Table 5 shows that the bars according to the invention (Examples 5 and 8) are superior to the controls in that the mush and sog are reduced significantly while the physical properties such as hardness indicating the processability of the bar being maintained. The rate of wear is improved indicating the ease of application of the bar on the fabric during use. The lather generated even in presence of soil is significantly improved. The amount of lather generation is generally taken as a cue to performance. The reduced mush and sog and improved lather and rate of wear would amount to superior economy of the bar in use.

Claims

1. A synergistic detergent bar composition comprising 0.1 to 5 wt% of soap, 5- 40 wt% of a non-soap detergent active component selected from the group including anionic, nonionic, cationic, zwitterionic detergent actives or mixtures thereof said bar composition being essentially free from dihydric alcohol.

2. A composition according claim 1 characterised in that the composition comprises from 10 to 30% of the non-soap detergent active component.

3. A composition according to any preceding claim characterised in that the soap is derived from at least one triglyceride selected from the group including tallow, tallow stearines, palm oil, palm stearines, soya bean oil, fish oil, caster oil, rice bran oil, sunflower oil, coconut oil, babassu oil and palm kernel oil.

4. A composition according claim 1 characterised in that the non-soap detergent active comprises at least one anionic detergent active compound.

5. A composition according claim 4 characterised in that the anionic detergent active compounds is selected from the group including the alkali metal and alkaline earth metal salts of higher alkyl benzene sulphonates, olefin sulphonates, higher alkyl sulphates, higher fatty acid monoglyceride sulphates and mixtures thereof.

6. A composition according to any preceding claim characterised in that the composition further comprises from 1 to 50% by wt of at least one detergency builder preferably selected from the group including alkali metal aluminosilicates, alkali metal carbonate, sodium tripolyphosphate, tetrasodium pyrophosphate, citrates, sodium nitrilotriacetate and combinations of these.

7. A composition according to any preceding claim characterised in that the composition further comprises from 15-45 wt%, of at least one abrasive, preferably selected from the group including, mixtures of calcium and magnesium carbonates, potassium sulphate, alumina, hydrated alumina, feldspars, talc, silica and mixtures thereof.

8. A composition according to any preceding claim characterised in that the composition further comprises from 10 to 75% by weight fillers preferably selected from the group including kaolin, calcium carbonate (calcite), soapstone, china clay and mixtures thereof.