|Title of Invention||
A PARTICULATE LAUNDRY DETERGENT COMPOSITION
|Abstract||A particulate laundry detergent composition comprising a major proportion of white or light-coloured particles and a minor proportion of visually contrasting particles of material capable of imparting colour and fluorescence to the resulting solution or dispersion when the composition is dissolved or dispersed in water, whereby the composition provides a coloured fluorescent solution or dispersion when dissolved or dispersed in water at a concentration within the range of from 1 to 10 g/l.|
|Full Text||FORM -2
THE PATENTS ACT, 1970 (39 of 1970)
(See Section 10)
HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.
The present invention relates to a particulate laundry detergent composition 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. However, the presence of the coloured speckles does not normally manifest itself in the wash liquor once the powder has been dissolved.
In our co-pending application No. 73/MUM/2001 there is provided a particulate laundry detergent composition comprising a major proportion of white or light-coloured particles and a minor proportion of visually contrasting bodies of significantly larger average particule size in at least one dimension than the average particle size of the white or light-coloured particles, the bodies being in the shape of small tablets or pastilles.
The present inventors now propose that the distinctive appearance conferred by coloured speckles or other visually contrasting particles may be carried over into the wash liquor itself. This may act as a further cue to the consumer, for example, to provide reassurance that some functional ingredient is present and effective in the wash liquor, or as a prompt to add more product where an insufficient amount has been used.
JP 49 081 410A (Dainichi Seiko Colour & Chemicals) discloses a detergent powder composition containing granules g
comprising a pH indicator. The indicator granules may contain very small quantities of dyes, pigments or fluorescent dyes so that they are visible in the detergent composition. For example, the granules, which are used at a concentration of 2 parts per 10 0 parts of detergent composition, may contain 0.4 wt% of a 1% Rhodamine B pigment (99 wt% polyvinyl chloride, 1 wt% Rhodamine B).
WO 99 07817A (Procter & Gamble) discloses an indicator system for use in a detergent composition, the indicator system comprising a dye particle and a coated delayed-release bleach particle, whereby the dye particle initially colours the wash liquor and the bleach particle subsequently decolourises it.
GB 801 018 (Thomas Hedley) discloses a detergent composition which appears colourless but contains finely divided and thoroughly distributed dye particles, whereby the apparently colourless composition provides a coloured wash liquor.
US 4 082 682 (Colgate-Palmolive) discloses white or lightly coloured detergent powders containing contrastingly coloured elongate soap particles (noodles).
DEFINITION OF THE INVENTION
The present invention provides a particulate laundry detergent composition comprising a major proportion of white oFlight-coloured particles and a minor proportion of visually contrasting particles of material capable of imparting colour and fluorescence to the resulting solution or dispersion when the composition is dissolved or dispersed in water, whereby the composition provides a coloured fluorescent solution or dispersion when dissolved or dispersed in water at a concentration within the range of from 1 to 10 g/1.
DETAILED DESCRIPTION OF THE INVENTION
The visually contrasting particles
According to the invention, the visually contrasting particles are capable of conferring fluorescent colour to the wash liquor when the product is dissolved or dispersed in water.
The concentrations at which laundry powders are used will vary depending on the formulation and on the laundry method used, for example, handwash or machine wash. However, the visually constrasting particles should contain sufficient coloured fluorescent material, and be present in a sufficient amount, that a coloured fluorescent solution or dispersion is obtained at product concentrations of from 1 to 10 g/litre.
Examples of suitable fluorescent materials capable of imparting fluorescent colour to the wash liquor include fluorescein (orange/yellow particles, fluorescent yellow solution) and;rhodamine B (deep purplish pink particles, fluorescent pink solution).
The fluorescent materials may be deposited onto particulate carrier materials, for example, sodium metasilicate or sodium citrate, to prepare particles suitable for incorporation into laundry detergent powders.
As well as providing an unusual and attractive appearance in both the dry product and the wash liquor, the fluorescent materials may deliver some fluorescer to the fabrics which makes white and light-coloured fabrics appear more white and bright.
According to a preferred embodiment of the invention, aimed especially at the handwash, the detergent composition also comprises visually contrasting particles comprising a pH indicator which is coloured at high pH and colourless, or differently coloured, at lower pH values. In this embodiment of the invention the wash liquor will initially be coloured, and as soiled fabrics are added and the pH falls, the liquor will change colour, the fluorescent effect from the fluorescent particles remaining throughout. This colour change acts as a cue to the consumer that the product has been exhausted, or that insufficient product has been used, and that more should be added.
In this embodiment of the invention, it is necessary to select an indicator that changes colour at an appropriate pH. This will generally be in the region of 7 to 10. Preferably the colour change occurs at a pH within the range of from 8 to 10.
It is also preferred to use an indicator which initially, at higher pH values, provides a blue solution. Some blue colour is then delivered to the fabrics, which for white fabrics improves whiteness and brightness and masks any yellowing that may have occurred in previous washes.
A suitable indicator is thymolphthalein which provides a blue solution at higher pH values and is colourless at lower pH values. The colour change occurs at a pH of about 9.
As with the fluorescent materials, indicators may be deposited onto particulate carrier materials, for example, sodium metasilicate or sodium citrate, to prepare particles suitable for incorporation into laundry detergent powders.
The amount of visually contrasting particles in the laundry detergent powder of the invention may suitably lie within the range of from 0.2 to 5 wt%, preferably from 0.5 to 2 wt%.
They are most suitably incorporated in particulate laundry detergent compositions by dry mixing.
The laundry detergent compositions of the invention also contain other conventional detergent ingredients. Essential ingredients are surfactants (detergent-active compounds) and detergency builders, and other conventional ingredients may optionally be present.
Detergent compositions of the invention may suitably comprise from 5 to 60 wt% of one or more detergent surfactants and from 10 to 80 wt% of one or more detergency builders, 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.
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 C8-C15; primary and secondary alkylsulphates, particularly C8-Ci5 primary alkyl sulphates;.alky1 ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.
Nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the Cs-C2o aliphatic alcohols ethoxylated with an average of from 1 to 2 0 moles of ethylene oxide per mole of alcohol, and more especially the C10-C15 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 alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide).
Cationic surfactants that may be used include quaternary ammonium salts of the general formula RiR2R3R4N+ X" wherein the R groups are long or short hydrocarbyl chains, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a solubilising cation (for example, compounds in which Rx is a C8-C22 alkyl group, preferably a C8-C10 or C12-C14 alkyl group, R2 is a methyl group, and R3 and R4, 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 RiR2R3R4N+ X", Ri represents a C8-Ci0 or Ci2-C14 alkyl group, R2 and R3 represent methyl groups, and R4 presents a hydroxyethyl group.
Amphoteric surfactants, for example, amine 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% by weight.
Nonionic surfactant, if present, is preferably used in an amount within the range of from 1 to 20% by weight.
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%, preferably from 15 to 70% by weight, of detergency builder. Preferably, the quantity of builder is in the range of from 15 to 50% by weight.
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 Doucif (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.
Organic builders that may be present 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,
hydroxyethyliminodiacetates, 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 3 0 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 lipases 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 Chimie).
Other ingredients that may be present include solvents, hydrotropes, fluorescers, photobleaches, foam boosters or foam controllers (antifoams) as appropriate, sodium carbonate, sodium bicarbonate, sodium silicate, sodium sulphate, calcium chloride, other inorganic salts, flow aids such as silicas and amorphous aluminosilicates, fabric conditioning compounds, and perfumes.
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, as previously indicated, the visually contrasting particles are preferably incorporated by postdosing (dry mixing).
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.
EXAMPLES 1 to 3
Preparation of visually contrasting particles
Example 1: Fluorescein crystals
Fluorescein (ex Merck) was dissolved in ethanol and the solution sprayed onto anhydrous sodium metasilicate (ex Ausimont), and the ethanol was then evaporated off. Yellow/orange crystals were obtained.
Example 2: Rhodamine B crystals
Rhodamine B (ex Merck) was dissolved in ethanol and the solution sprayed onto sodium citrate (ex Haarman & Reimer). The ethanol was evaporated off to leave purplish pink crystals.
Example 3: Thymolphthalein crystals
The blue dye thymolphthalein was dissolved in a mixture of 70 wt% ethanol and 30 wt% water (the use of water intensifies the blue colour). The solution was sprayed onto anhydrous sodium metasilicate particles (ex Ausimont). The ethanol and water were evaporated off to give deep blue crystals.
Detergent powder containing fluorescent crystals
A detergent powder having the following formulation was prepared by conventional spray-drying and postdosing techniques. The fluorescent particles were postdosed.
The composition consisted of a major proportion of white particles with a minor but very noticeable proportion of bright orange/yellow particles.
A sample of the composition was dissolved in water to a concentration of 4 g/litre. The solution was fluorescent yellow in colour.
Detergent powder containing fluorescent crystals
Example 4 was repeated using the rhodamine B crystals of Example 2 (1 wt%) instead of the fluorescein crystals of Example 1. The composition consisted of a major proportion of white particles with a minor but very noticeable proportion of vividly coloured purplish pink particles. A sample of the composition was dissolved in water to a concentration of 4 g/litre. The solution was fluorescent pink in colour.
Detergent composition containing indicator particles
The procedure of Example 4 was repeated using the thymolphthalein crystals of Example 3 (1 wt%, replacing sodium sulphate) in addition to the fluorescein particles. The composition consisted of a major proportion of white particles with minor but very noticeable proportions of minor but very noticeable proportion of vividly coloured purplish pink particles and dark blue particles. A sample of the composition was dissolved in water to a concentration of 4 g/litre. The solution was purplish blue in colour. The pH was about 11. The pH was lowered to 9 by addition of dilute aqueous acid. The solution became pink with change in pH.
1. A particulate laundry detergent composition comprising a major proportion of white or light-coloured particles and a minor proportion of visually contrasting particles of material capable of imparting colour and fluorescence to the resulting solution or dispersion when the composition is dissolved or dispersed in water, whereby the composition provides a coloured fluorescent solution or dispersion when dissolved or dispersed in water at a concentration within the range of from 1 to 10 g/l.
2. A composition as claimed in claim 1 wherein the visually contrasting particles are present in an amount of from 0.2 to 5 wt% preferably from 0.5 to 2 wt%.
3. A composition as claimed in anyone of claims 1 or 2 wherein the visually
contrasting particles can be selected from fluoresceince and rhodamine B.
4. A composition as claimed in anyone of claims 1 to 3 wherein the visually contrasting particles comprise an indicator which is coloured at higher pH values and colourless or differently coloured at lower pH values.
5. A composition as claimed in claim 4 wherein said indicator has a colour change at a pH within the range of from 8 to 10.
6. A composition as claimed in anyone of claims 4 or 5 wherein the visually contrasting particles comprise thymolphthalein.
7. A composition as claimed in any preceding claims comprising from 5 to 60 wt% of detergent active material, from 10 to 80 wt% of detergency builder, from 0.5 to 5 wt% of visually contrasting particles, and optionally other detergent ingredients to 100 wt%.
8. A particulate laundry detergent composition substantially as herein described hereinbefore in anyone of Examples 4 to 6.
Dated this 23rd day of January 2001
|Indian Patent Application Number||71/MUM/2001|
|PG Journal Number||41/2007|
|Date of Filing||23-Jan-2001|
|Name of Patentee||HINDUSTAN LEVER LIMITED|
|Applicant Address||HINDUSTAN LEVER HOUSE, 165/166, BACKBAY RECLAMATION, MUMBAI,|
|PCT International Classification Number||N/A|
|PCT International Application Number||N/A|
|PCT International Filing date|