COLOURED SPECKLE COMPOSITION AND PARTICULATE LAUNDRY DETERGENT COMPOSITIONS CONTAINING IT

Abstract: A coloured speckle composition for use in laundry detergent powders and tablets is based on sodium chloride. The speckles exhibit excellent dissolution behaviour and flow properties, and no staining of fabrics in the wash is observed. The speckle composition is used both in white powders and in powders having a contrasting colour, for example, red speckles may be used in a white or blue powder

Description: COLOURED SPECKLE COMPOSITION AND PARTICULATE LAUNDRY DETERGENT COMPOSITIONS CONTAINING IT TECHNICAL FIELD The present invention relates to a coloured particulate material and its use as speckles in particulate laundry detergent compositions for use in laundering fabrics by hand or machine . BACKGROUND AND PRIOR ART It is well known to include visually contrasting particles, for example, coloured speckles or noodles, in laundry detergent powders. These may be included as a cue to the consumer, to indicate the presence of some specific ingredient, for example, bleach, or may simply be present to give the product an attractive appearance. Problems that have been observed with previously proposed speckle compositions include poor dissolution, poor flow properties, and a tendency for the colourant to stain fabrics in the wash. Speckles based on various carrier materials have been disclosed in the prior art. GB 1 546 139 (Procter & Gamble) discloses coloured speckles in which a colourant is carried on hydratable alkaline inorganic salt, for example, sodium tripolyphosphate, sodium carbonate or sodium tetraborate . US 5 606 883 (Bernard et al) discloses coloured speckle agglomerates comprising zeolite, nonionic surfactant, colourant, binding agent and water. EP 19413A (Unilever) discloses coloured speckles based on a solid surfactant, for example, a highly-ethoxylated nonionic surfactant . EP 60728A (Unilever) discloses coloured speckles prepared by spraying a detergent base powder with an aqueous colourant solution which also contains a hydratable salt, preferably a phosphate, carbonate or sulphate. GB 2 199 338A (Unilever) discloses coloured speckles prepared by mixing a detergent base powder with a dyestuff and treating with a binder which is preferably a water- soluble polymer (e.g. acrylic/maleic copolymer) or a nonionic surfactant. WO 99/51714A (Unilever) discloses coloured speckles in which the principal carrier material is an alpha-hydroxy carboxylic acid, preferably citric acid. Other materials that have been proposed as bases for coloured speckles include soap, sodium metasilicate, and clays . WO 90 00006A (PPG Industries Inc) discloses a particulate halogen bleaching composition, for example, calcium hypochlorite, containing about 0.1 to 10 wt% of a colourant- treated particulate inorganic water-soluble salt, for example, sodium chloride. US 4 992 193 (Lever Brothers) discloses a conventional detergent powder containing soap-based noodles (but not speckles) which comprise 2-5 wt% inorganic salt (sodium chloride is specifically disclosed) and optionally up to 0.1 wt% dyestuff. US 3850833 (Colgate-Palmolive) discloses coloured particles consisting of sodium chloride, potassium chloride and/or sodium sulphate for incorporation into a scouring cleanser composition. SUMMARY OF THE INVENTION The present inventors have now discovered that coloured speckles for use in laundry detergent compositions may advantageously be based on sodium chloride. Sodium chloride is stable, inert, highly water-soluble, and compatible with all ingredients used in laundry detergent compositions. The speckles exhibit excellent dissolution behaviour and flow properties, and no staining of fabrics in the wash is observed. DEFINITION OF THE INVENTION The present invention accordingly provides a particulate laundry detergent composition comprising a minor proportion of a coloured speckle composition having a colour contrasting with that of the major proportion of the composition, wherein the coloured speckle composition comprises sodium chloride and a colourant. The present invention also provides a coloured particulate composition for use as a speckle composition in a particulate laundry detergent composition, which coloured particulate composition comprises: (a) from 90 to 99.5 wt%, preferably from 95 to 99 wt%, of sodium chloride, (b) from 0.01 to 6 wt%, preferably from 0.02 to 0.5 wt%, of a colourant, and at least one of: (cl) from 0.1 to 10 wt%, preferably from 0.2 to 5 wt%, of silica, (c2) from 0.1 to 10 wt%, preferably from 0.2 to 1 wt%, of a flow aid other than a silica, (c3) from 0.01 to 3 wt%, preferably from 0.02 to 0.5 wt%, of an opaque white pigment and, (c4) from 0.05 to 5 wt%, preferably from 0.1 to 1 wt%, of a binder . DETAILED DESCRIPTION OF THE INVENTION The Speckle Composition The coloured speckle composition of the invention contains a major proportion, preferably at least 90 wt%, of sodium chloride. Preferably the speckle composition contains from 90 to 99.5 wt%, more preferably from 95 to 99 wt%, of sodium chloride . Also essential is a colourant. This may be a pigment, or a water-dispersible dye. Preferred colours are red and blue. A preferred pigment is Pigment Red CI 12490. Suitable blue colourants are phthalocyanines . The colourant is suitably present in an amount of from 0.01 to 6 wt%, preferably from 0.02 to 0.5 wt%, based on the speckle composition. Preferably an opaque white pigment is present to give the speckle particles sufficient opacity. A suitable material is titanium dioxide. The opaque white pigment is suitably- present in an amount of from 0.01 to 3 wt%, preferably from 0.02 to 0.5 wt%. According to a preferred embodiment of the invention the speckle composition contains silica, to provide a protective outer coating on the speckles and to improve flow. Silica is suitably present in an amount of from 0.1 to 10 wt%, preferably from 0.2 to 5 wt% . The speckle composition preferably also contains a flow aid other than a silica. Suitable flow aids are selected from silicates and aluminosilicates . The flow aid is suitably present in an amount of from 0.1 to 10 wt%, preferably from 0.2 to 1 wt%. Preferably the speckle composition also contains a binder. Preferred binders are polymers, for example, cellulosic materials, for example, sodium carboxymethyl cellulose, or acrylic polymers, for example, acrylic/maleic copolymers such as Sokalan (Trade Mark) CP5 ex BASF. Other organic film-forming materials may be envisaged, for example, polyethylene glycols or highly ethoxylated nonionic surfactants. An especially preferred binder is sodium carboxymethyl cellulose. The binder is suitably present in an amount of from 0.05 to 5 wt%, preferably from 0.1 to 1 wt%. Preparation of the Speckle Composition The speckle composition may be prepared by any convenient method for treating the sodium chloride with the colourant. Any suitable mixing apparatus may be used. The mixer should have a stainless steel or other inert interior surface in view of the corrosive properties of sodium chloride. In a preferred procedure, the sodium chloride is dosed into a mixer, and a premix of the colourant, the opaque white pigment and the binder then added. If silica is incorporated, a minor proportion of the silica is preferably added with the sodium chloride, and the major proportion added after addition of the colourant premix. Flow aid is preferably added last. After thorough mixing to ensure homogeneity, the composition is dried. Detergent Compositions The coloured speckle composition of the invention is suitable for use in both white and coloured detergent compositions, provided that there is sufficient contrast between the colour of the major proportion of the powder and the colour of the speckles . Thus the detergent composition may comprise a major proportion of white or light-coloured particles and a minor proportion of the coloured speckle composition. Alternatively, the detergent composition may comprise a major proportion of particles having a first colour, for example, blue, and a minor proportion of the coloured speckle composition having a second colour contrasting with the first colour, for example, red. The speckle composition is preferably present in an amount of from 0.01 to 15 wt%, preferably from 0.1 to 10 wt%, more preferably from 1 to 10 wt% and most pre erably from 2 to 8 wt%. Detergent compositions according to the invention contain, as well as the speckle composition, conventional detergent ingredients, notably detergent-active materials (surfactants), and preferably also detergency builders. Heavy-duty laundry detergent compositions in accordance with the invention may suitably comprise from 5 to 60 wt% of detergent-active material, from 10 to 80 wt% of detergency builder, from 0.1 to 10 wt% of the speckles, and optionally other detergent ingredients to 100 wt% . The detergent compositions will contain, as essential ingredients, one or more detergent active compounds (surfactants) which may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent active compounds, and mixtures thereof. Many suitable detergent active compounds are available and are fully described in the literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch. The preferred detergent active compounds that can be used are soaps and synthetic non-soap anionic and nonionic compounds. Non-soap anionic surfactants are especially preferred. Non-soap anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates , particularly linear alkylbenzene sulphonates having an alkyl chain length of C 8 -C15; primary and secondary alkylsulphates, particularly C 8 -C 15 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred. A preferred anionic surfactant is linear alkylbenzene sulphonate . Nonionic surfactants may optionally be present. These include the primary and secondary alcohol ethoxylates, especially the C 8 -C2 0 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and more especially the C1 0 -C 15 primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated nonionic surfactants include alkylpoly- glycosides, glycerol monoethers, and polyhydroxya ides (glucamide) . Cationic surfactants may optionally be present. These include quaternary ammonium salts of the general formula R 1 R 2 R 3 R 4 N X wherein the R groups are long or short hydrocarbyl chains, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a solubilising anion (for example, compounds in which Ri is a C8-C2 2 alkyl group, preferably a Cs-Cio or C1 2 -C1 4 alkyl group, R2 is a methyl group, and R 3 and R 4 , which may be the same or different, are methyl or hydroxyethyl groups) ; and cationic esters (for example, choline esters) . In an especially preferred cationic surfactant of the general formula R1R2R 3 R 4 N X , Ri represents a CS-C Q or C 1 2- C 14 alkyl group, R 2 and R 3 represent methyl groups, R 4 presents a hydroxyethyl group, and X represents a halide or methosulphate ion. Optionally, amphoteric surfactants, for example, a ine oxides, and zwitterionic surfactants, for example, betaines, may also be present. Preferably, the quantity of anionic surfactant is in the range of from 5 to 50% by weight of the total composition. More preferably, the quantity of anionic surfactant is in the range of from 8 to 35 wt%, most preferably from 10 to 30 wt% Nonionic surfactant, if present, is preferably used in an amount within the range of from 1 to 20 wt% . The total amount of surfactant present is preferably within the range of from 5 to 60 wt% . The compositions may suitably contain from 10 to 80 wt%, preferably from 15 to 70 wt%, of detergency builder. Preferably, the quantity of builder is in the range of from 15 to 50 wt%. The detergent compositions may contain as builder a crystalline aluminosilicate, preferably an alkali metal aluminosilicate, more preferably a sodium aluminosilicate (zeolite) . The zeolite used as a builder may be the commercially available zeolite A (zeolite 4A) now widely used in laundry detergent powders. Alternatively, the zeolite may be maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070B (Unilever) , and commercially available as Doucil (Trade Mark) A24 from Crosfield Chemicals Ltd, UK. Zeolite MAP is defined as an alkali metal aluminosilicate of zeolite P type having a silicon to aluminium ratio not exceeding 1.33, preferably within the range of from 0.90 to 1.33, preferably within the range of from 0.90 to 1.20. Especially preferred is zeolite MAP having a silicon to aluminium ratio not exceeding 1.07, more preferably about 1.00. The particle size of the zeolite is not critical. Zeolite A or zeolite MAP of any suitable particle size may be used. Also preferred according to the present invention are phosphate builders, especially sodium tripolyphosphate. This may be used in combination with sodium orthophosphate, and/or sodium pyrophosphate. Other inorganic builders that may be present additionally or alternatively include sodium carbonate, layered silicate, amorphous aluminosilicates . Most preferably, the builder is selected from sodium tripolyphosphate, zeolite, sodium carbonate, and combinations thereof . Organic builders may optionally be present. These include polycarboxylate polymers such as polyacrylates and acrylic/maleic copolymers; polyaspartates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-di- and trisuccinates, carboxymethyloxysuccinates , carboxy-methyloxymalonates , dipicolinates , hydroxyethyl iminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts . Organic builders may be used in minor amounts as supplements to inorganic builders such as phosphates and zeolites. Especially preferred supplementary organic builders are citrates, suitably used in amounts of from 5 to 30 wt %, preferably from 10 to 25 wt %; and acrylic polymers, more especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt %, preferably from 1 to 10 wt% . Builders, both inorganic and organic, are preferably present in alkali metal salt, especially sodium salt, form. Detergent compositions according to the invention may also suitably contain a bleach system, although non-bleaching formulations are also within the scope of the invention. The bleach system is preferably based on peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids , capable of yielding hydrogen peroxide in aqueous solution. Suitable peroxy bleach compounds include organic peroxides such as urea peroxide, and inorganic persalts such as the alkali metal perborates, percarbonates , perphosphates , persilicates and persulphates . Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate . The peroxy bleach compound is suitably present in an amount of from 5 to 35 wt%, preferably from 10 to 25 wt% . The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 1 to 8 wt%, preferably from 2 to 5 wt% . Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and peroxybenzoic acid precursors; and peroxycarbonic acid precursors. An especially preferred bleach precursor suitable for use in the present invention is N,N,N',N'- tetracetyl ethylenediamine (TAED) . A bleach stabiliser (heavy metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetraacetate (EDTA) and the polyphosphonates such as Dequest (Trade Mark), EDTMP. The detergent compositions may also contain one or more enzymes. Suitable enzymes include the proteases, amylases, cellulases, oxidases, peroxidases and Upases usable for incorporation in detergent compositions. Preferred proteolytic enzymes (proteases) are catalytically active protein materials which degrade or alter protein types of stains when present as in fabric stains in a hydrolysis reaction. They may be of any suitable origin, such as vegetable, animal, bacterial or yeast origin. Proteolytic enzymes or proteases of various qualities and origins and having activity in various pH ranges of from 4-12 are available. Proteases of both high and low isoelectric point are suitable. Other enzymes that may suitably be present include lipases, amylases, and cellulases including high-activity cellulases such as Carezyme ex Novo . In particulate detergent compositions, detergency enzymes are commonly employed in granular form in amounts of from about 0.1 to about 3.0 wt% . However, any suitable physical form of enzyme may be used in any effective amount. Antiredeposition agents, for example, cellulose esters and ethers, for example sodium carboxymethyl cellulose, may also be present . The compositions may also contain soil release polymers, for example sulphonated and unsulphonated PET/POET polymers, both end-capped and non-end-capped, and polyethylene glycol/polyvinyl alcohol graft copolymers such as Sokolan (Trade Mark) HP22. Especially preferred soil release polymers are the sulphonated non-end-capped polyesters described and claimed in WO 95 32997A (Rhodia Chi ie) . The detergent compositions may also include one or more inorganic salts other than builder salts. These may include, for example, sodium bicarbonate, sodium silicate, sodium sulphate, magnesium sulphate, calcium sulphate, calcium chloride and sodium chloride. Preferred inorganic salts are sodium sulphate, sodium chloride, and combinations thereof. The coloured speckle composition is especially suitable for incorporation in detergent compositions which contain sodium chloride in addition to that present in the speckle composition. The detergent compositions may also contain other inorganic materials, for example, calcite, silica, amorphous aluminosilicate, or clays. Other ingredients that may be present include solvents, hydrotropes, fluorescers, dyes, photobleaches, foam boosters or foam controllers (antifoams) as appropriate, fabric conditioning compounds, and perfumes. An especially preferred detergent composition according to the invention comprises: (i) from 10 to 30 wt% of linear alkylbenzene sulphonate, (ii) from 5 to 60 wt% of detergency builder selected from sodium tripolyphosphate, sodium carbonate, zeolite and combinations thereof, (iii) from 0 to 50 wt% of sodium chloride, (iv) from 1 to 10 wt% of the coloured speckle composition, (v) optionally other minor ingredients to 100 wt%, preferably selected from sodium carboxymethyl cellulose, sodium sulphate, bentonite clay, fluorescer, dye of a contrasting colour to that of the coloured speckle composition, and perfume. The detergent compositions of the invention may be in powder or tablet form. Powders of low to moderate bulk density may be prepared by spray-drying a slurry, and optionally postdosing (dry- mixing) further ingredients. "Concentrated" or "compact" powders may be prepared by mixing and granulating processes, for example, using a high-speed mixer/granulator, or other non-tower processes. In both types of powder, the speckle composition may be incorporated by postdosing (dry mixing) . The detergent composition of the invention may alternatively be in tablet form. Tablets may be prepared by compacting powders, especially "concentrated" or "compact" powders, prepared as described above. The speckle composition is then included in the powder prior to compaction. EXAMPLES The invention will now be illustrated in further detail by means of the following Examples, in which parts and percentages are by weight unless otherwise stated. Example 1: Pink Speckle Composition A speckle composition was prepared to the following formulation: The composition was prepared as follows . The ingredients were introduced into a stainless steel mixer in the following order: 1. Sodium chloride 2. Silica (0.33 wt%) 3. Pigment solution (titanium dioxide, red colourant, sodium carboxymethyl cellulose) 4. Silica (rest) 5. Zeolite The ingredients were mixed for a period of time sufficient to ensure homogeneity, and the resulting particulate material then dried. The speckles were of an attractive pink colour. Comparative Examples A to C Speckles using the same colourant were prepared using the following materials instead of sodium chloride: Detergent Compositions The speckle compositions of Example 1 and Comparative Examples A, B and C were introduced, at a level of 4 wt%, into samples of a laundry detergent powder having the following formulation: The pink speckles of Example 1 had a strong visual impact giving the product an attractive appearance. On storage no loss of colour from the speckles was observed. Dissolution and Staining Test The detergent compositions and speckle compositions were tested for dissolution and for fabric staining. Dissolution was measured by a conductivity method. Staining was measured using hand bowl wash methodology. The fabrics used were knitted cotton, and polyester (67%) /cotton (33%) . Three different handwash methods were used: (i) the powder was dissolved in water in a bowl and the fabrics then added, (ii) the fabrics were placed in the water in the bowl and the powder then added, (iii) the fabrics were thoroughly wetted and a concentrated paste (powder and a little water) applied directly. In methods (i) and (ii) , the detergent compositions were used at a concentration in the wash liquor of 3.5 g/1. The fabrics were allowed to soak for 1 hour and for 2 hours, and the fabrics were then washed and rinsed. The speckle compositions were also placed directly onto wet fabrics for 1 hour and 2 hours of soak. The results were as follows: Only the sodium-chloride-based speckles of Example 1 gave good dissolution without any fabric staining. No staining was observed even under the most stressed conditions.

Claims: CLAIMS 1. A particulate laundry detergent composition comprising a minor proportion of a coloured speckle composition having a colour contrasting with that of the major proportion of the composition, characterised in that the coloured speckle composition comprises sodium chloride and a colourant . 2. A detergent composition as claimed in claim 1, characterised in that the coloured speckle composition comprises at least 90 wt% of sodium chloride. 3. A detergent composition as claimed in claim 1 or claim 2, characterised in that the coloured speckle composition comprises: (a) from 90 to 99.5 wt%, preferably from 95 to 99 wt%, of sodium chloride, (b) from 0.01 to 6 wt%, preferably from 0.02 to 0.5 wt%, of a colourant, (c) optionally from 0.1 to 10 wt%, preferably from 0.2 to 5 wt%, of silica, (d) optionally from 0.1 to 10 wt% , preferably from 0.2 to 1 wt%, of a flow aid other than a silica, (e) optionally from 0.01 to 3 wt%, preferably from 0.02 to 0.5 wt%, of an opaque white pigment, (f) optionally from 0.05 to 5 wt%, preferably from 0.1 to 1 wt%, of a binder. 4. A detergent composition as claimed in any preceding claim, characterised in that it comprises from 0.01 to 15 wt%, preferably from 0.1 to 10 wt%, more preferably from 1 to 10 wt%, of the coloured speckle composition. 5. A detergent composition as claimed in any preceding claim, characterised in that it further comprises sodium chloride additional to that present in the coloured speckle composition. 6. A detergent composition as claimed in any preceding claim, characterised in that it comprises a major proportion of white or light-coloured particles and a minor proportion of the coloured speckle composition. 7. A detergent composition as claimed in any one of claims 1 to 5 , characterised in that it comprises a major proportion of particles having a first colour and a minor proportion of the coloured speckle composition having a second colour contrasting with the first colour. A detergent composition as claimed in claim 7, characterised in that the major proportion of particles is blue and the coloured speckle composition is red. 9. A detergent composition as claimed in any preceding claim, characterised in that it comprises from 5 to 60 wt% of detergent-active material, from 10 to 80 wt% of detergency builder, from 0.1 to 10 wt% of the coloured speckle composition, and optionally other detergent ingredients to 100 wt% . 10. A detergent composition as claimed in claim 9, characterised in that it comprises: (i) from 10 to 30 wt% of linear alkylbenzene sulphonate, (ii) from 5 to 60 wt% of detergency builder selected from sodium tripolyphosphate, sodium carbonate, zeolite and combinations thereof, (iii) from 0 to 50 wt% of sodium chloride, (iv) from 1 to 10 wt% of the coloured speckle composition, (v) optionally other minor ingredients to 100 wt%, preferably selected from sodium carboxymethyl cellulose, sodium sulphate, bentonite clay, fluorescer, dye of a contrasting colour to that of the coloured speckle composition, and perfume. 11. A detergent composition as claimed in any preceding claim, characterised in that it is in powder or tablet form. 12. A coloured particulate composition for use as a speckle composition in a particulate laundry detergent composition, characterised in that the coloured particulate composition comprises: (a) from 90 to 99.5 wt%, preferably from 95 to 99 wt%, of sodium chloride, (b) from 0.01 to 6 wt%, preferably from 0.02 to 0.5 wt%, of a colourant, and at least one of : (cl) from 0.1 to 10 wt%, preferably from 0.2 to 5 wt%, of silica, (c2) from 0.1 to 10 wt%, preferably from 0.2 to 1 wt%, of a flow aid other than a silica, (c3) from 0.01 to 3 wt%, preferably from 0.02 to 0.5 wt%, of an opaque white pigment, (c4) from 0.05 to 5 wt%, preferably from 0.1 to 1 wt%, of a binder. 13. A coloured particulate composition as claimed in claim 12, characterised in that it comprises a flow aid (c2) selected from silicates, aluminosilicates and mixtures thereof. 14. A coloured particulate composition as claimed in claim 12 or claim 13, characterised in that the colourant (b) is a red or blue pigment. 15. A coloured particulate composition as claimed in any one of claims 12 to 14, characterised in that it comprises titanium dioxide as an opaque white pigment (c3) . 16. A coloured particulate composition as claimed in any one of claims 12 to 15, characterised in that it comprises a polymeric binder (c4) . 17. A coloured particulate composition as claimed in claim 16, characterised in that the polymeric binder (c4) is sodium carboxymethyl cellulose.

Inventors: CARRIEL SOLEDAD SCARLET RI, NUNZIO DEL MARIO JOVELINO, SCHIOZER ADRIANA LOPES, CARRIEL, SOLEDAD, SCARLET, RI, NUNZIO, DEL, MARIO, JOVELINO, SCHIOZER, ADRIANA, LOPES
Applicants: LEVER HINDUSTAN LTD, UNILEVER NV, UNILEVER PLC, HINDUSTAN LEVER LIMITED
Application year: 2001
Main classification: C11D3
IPC codes: C11D3