EP2195410B1

EP2195410B1 - Performance ingredients in film particles

Info

Publication number: EP2195410B1
Application number: EP08804761.8A
Authority: EP
Inventors: Stephen Norman Batchelor; Janette Cutrona; Rudolf Govert Van Driel; Kees Bert Geerse; Edwin Leo Mario Lempers
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2007-10-12
Filing date: 2008-09-25
Publication date: 2016-07-20
Anticipated expiration: 2028-09-25
Also published as: CL2008003020A1; BRPI0818084A2; ES2598487T3; WO2009047128A1; ZA201001429B; CN101878291A; EP2195410A1; AR068860A1

Description

This invention relates to granular detergent compositions comprising a plurality of film particles.

BACKGROUND

It is known to include visually contrasting particles in granular laundry detergent compositions. The contrasting particles may deliver a functional ingredient or may simply provide a visual cue to the user.
In US 4082682 , a minor proportion of contrastingly colored elongated soap particles is added to a detergent powder. The contrasting particles comprise a non fabric-substantive dye and a fluorescer. The powder comprises a detergency builder compound. The soap particles contribute detergency to the composition and reduce foaming. Because the soap particles could sink onto the fabric it is a stated advantage of the particles that they do not cause staining of the fabric with which they come into contact.
In GB2356403A a powder detergent composition having a major proportion of white or light-coloured particles has dry mixed into it a minor proportion of lamellar visually contrasting bodies of significantly larger average particle size in at least one dimension than the average particle size of the white or light-coloured particles. The examples used contrasting circular or star shaped bodies made of coloured water-soluble polymer film. The visually contrasting bodies may optionally contain detergent functional ingredients.
WO2006/079416 proposes to use a highly soluble film particle as a visual cue. It is suggested to be possible to include functional ingredients within the film e.g. surface active agents, perfume, antioxidant, antifoam. Examples in this application compare detergent powders containing 0.1 wt% visual cues made from polyvinyl alcohol with visual cues made from gum Arabic. Suitably, the film particles could be chosen to pass a 1400 µm sieve, but not a 500 µm sieve.
It is known to add sensitive ingredients to laundry powders as separately manufactured granules. This process may be referred to as dry mixing or post dosing.
US4176079 describes an alternative to post dosing granules. An enzyme is incorporated into a water soluble film and the functional film so produced is cut into squares, rectangles or strips and added to a detergent powder. Typical film additive compositions are polyvinyl alcohol 48.7 % and nonionic surfactant 43.8 % (balance water and enzyme). The cut functional film additive has a surface area of 300 mm².
US 2005/0075261 A1 relates to a water-soluble and/or water dispersible particle comprising an active ingredient, preferably an enzyme, in a matrix comprising from 20-95% of the particle of a specified polyvinylalcohol polymer. The examples make the particle by applying a chopping action to an extruded noodle. This would tend to make a granular
(spherical) particle. Other active ingredients suggested for inclusion at levels of 0.1 to 55% include; bleaches, bleach activators, bleach catalysts, brighteners and photobleaches. The particle size ranges from 200µm to 2000µm, preferably 250µm to 800µm. In an embodiment where the extruded (cylindrical) particle is not chopped up it can be up to 20mm long, but it is preferably less than 1mm long and has a preferred particle size distribution of 100µm to 800µm.
There remain a number of problems relating to the use of film particles in granular detergent compositions, especially granular laundry detergents.
A major problem is to make a visual cue film particle that aids cleaning. Surprisingly, we have now found new benefits from delivery of specific benefit ingredients from a film particle.

SUMMARY OF THE INVENTION

According to the present invention there is provided a granular detergent composition comprising a plurality of film particles, each film particle comprising at least 30% polyvinyl alcohol and 0.01 to 1 wt% of a benefit ingredient selected from the group comprising: shading dye characterised in that the thickness of each film particle is at most 0.5mm and the
cross sectional area of each film particle is between 4 mm² and 100mm².

DETAILED DESCRIPTION OF THE INVENTION

Granular laundry detergent compositions are mainly composed of surfactants and electrolytes. Typical surfactants include linear alkyl benzene sulphonates, primary alcohol sulphates, linear alcohol ethoxysulphates and alcohol ethoxylates. Typical electrolytes are inorganic materials such as sodium sulphate, sodium chloride, sodium tripolyphosphates, sodium carbonate, silicas, and zeolites and organic materials such as polycarboxylates and citric acid.
To give additional wash benefits, benefit ingredients; namely fluorescers, shading dyes, photobleaches antioxidant and catalysts, may be included at low levels. Such benefit ingredients are most cost-effective when added at very low levels, topically less than 0.1 wt% of the composition. The benefit ingredients are usually granulated and then post-dosed into the granular composition. This inevitably results in localised high concentrations of the benefit ingredient, which can cause problems if they come into contact with certain fabrics before they have had an opportunity to dissolve or disperse into the wash liquor. This problem is caused by the localised high concentration of the benefit ingredient and not by the timing of its release. The problem occurs particularly for low molecular weight benefit ingredients that cause damage to fabrics when present at very high concentrations, particularly if delivered from a carrier substrate that has a higher solubility and/or dispersibilty than the benefit ingredient.
Encapsulation of the benefit ingredient or ingredients within soluble polymeric film particles provides a solution to this problem. The amount of benefit ingredient in the film particle is preferably 0.05 to 1.0 wt% of the film particle.
The film particles are desirably rendered visible by non fabric-substantive dye that gives them a contrasting colour from the granules making up the remainder of the granular composition.
Granular detergent compositions of lighter colour than the film particles advantageously include some fluorescer and/or shading dye in the granules to give a higher contrast between the granules and the film particles.
The granular detergent composition is preferably highly alkaline when dissolved in deionised water. A 0.1% solution at 25 °C is > pH 10.5. To achieve this pH the granular detergent composition may advantageously comprise silicate and/or carbonate.
The film particle is preferably more near to a neutral pH to protect the benefit ingredient or ingredients contained therein. It has a pH of 3 to 9, preferably 6 to 8 when dissolved to form a 0.1% solution in deionised water.
Although many soluble polymers could be suitable for inclusion in the film particle, The film particle comprises at least 30% polyvinyl alcohol. To improve its solubility and to facilitate easy inclusion of the benefit ingredients the film particles desirably further comprise 5 to 50 wt% surfactant. Preferred surfactant content of the film particles is at least 5 wt% anionic surfactant, most preferably an alkyl sulphate.
Optional further ingredients are: adjuncts to assist in the manufacture of the film, for instance release agents and waster. Besides its effect of control of relative humidity of the film, water also assists in plasticising the film and regulates its solubility.
The polymer may be selected from water soluble film forming polymers, especially those used in formulation of detergent powders. Preferred polymers include polymers which dissolve and/disperse completely in water within 30 minutes with agitation at a temperature anywhere in the range of from 293 to 333K.
Preferred water soluble polymers are those capable of being cast into a film or solid mass, for example as described in Davidson and Sittig, Water-Soluble Resins, Van Nostrand Reinhold Company, New York (1968). Preferred water-soluble resins include polyvinyl alcohol, cellulose ethers, polyethylene oxide, starch, polyvinylpyrrolidone, polyacrylamide, polyvinyl methyl ether-maleic anhydride, polymaleic anhydride, styrene maleic anhydride, hydroxyethylcellulose, hydroxypropylmethylcellulose, polyethylene glycols, carboxymethylcellulose, polyacrylic acid salts, alginates, acrylamide copolymers, guar gum, casein, ethylene-maleic anhydride resin series, polyethyleneimine, ethyl hydroxyethylcellulose, ethyl methylcellulose, hydroxyethyl methylcellulose, sugars. Lower molecular weight water-soluble, polyvinyl alcohol film-forming resins are preferred.
Polyvinyl, alcohols preferred for use therein have an average molecular weight anywhere between 1,000 and 1,000,000, preferably between 5,00C and 250,000, for example between 15,000 and 150,000. Hydrolysis, or alcoholysis, is defined as the percent completion of the reaction where acetate groups on the resin are substituted with hydroxyl, -OH, groups, A hydrolysis range of from 60-99% of polyvinyl alcohol film-forming resin is preferred, while a more preferred range of hydrolyses is from about 70-90% for water-soluble, polyvinyl alcohol film-forming resins. The most preferred range of hydrolysis is 80-89%. As used in this application, the term "polyvinyl alcohol" includes polyvinyl acetate compounds with levels of hydroloysis disclosed herein.
Another suitable polymer is a polyvinyl alcohol film, made of a polyvinyl alcohol copolymer having a comonomer having a carboxylate function.
The preferred grade of PVA picks up water only at an RH well above that of granular detergent compositions. Thereby, it protects the other film ingredients from decomposition by water and soluble dyes from bleeding.
The visual cue film particle may comprise 10 to 80% polymer or polymer mixture.
Although any suitable surfactant or surfactant system may be used, the surfactant is preferably an anionic surfactant, especially if the granular composition comprises a builder.
Suitable anionic surfactants include are well-known to those skilled in the art. Examples of high-foaming sulphonate or sulphate type surfactants include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C₆-C₁₅; primary and secondary alkylsulphates, particularly C₆-C₁₅ primary alkyl sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.
Further information is given in the open literature, for example, in "Surface-Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch.
The preferred anionic surfactants are alkylbenzene sulphonates, more especially linear alkylbenzene sulphonate (LAS), which is preferably present in an amount of from 12 to 24 wt%, more preferably from 12 to 22 wt% and especially from 15 to 22 wt%.
Even more preferred are primary alcohol sulphates (PAS), particularly C₈-C₁₈, preferably C₁₂-C₁₅, primary alcohol sulphates. A particularly preferred surfactant is primary alcohol sulphate (PAS) with a carbon chain length of 12. Visual cue Film particles containing up to 50 % PAS, may be used.
The film may additionally include a second surfactant. The second surfactant is preferably chosen from amphoteric surfactants, zwitterionic surfactants, nonionic surfactants and ethoxylated anionic surfactants.
Preferred amphoteric second surfactants are amine oxides. The most preferred amine oxide is coco dimethylamine oxide.
Preferred zwitterionic second surfactants are betaines, and especially amidobetaines, for example, coco amidopropyl betaine.
Preferred nonionic second surfactants include the primary and secondary alcohol ethoxylates, especially the C8-C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 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.
Preferred ethoxylated anionic second surfactants, include alkyl ether sulphates (ethoxylated alcohol sulphates).
Also suitable for use as second surfactants in the visual cues of the present invention are C₈-C₁₈ alkyl monoethanolamides, for example, coco monoethanolamide.
The second surfactant system used in the film particle may additionally comprise minor amounts, e.g. less than 5% of the film, of cationic surfactant.
Surfactant may be included at a level of up to 90 wt%, preferably up to 75 wt%, most preferably up to 60 wt% in the film.
The visual cue needs to be easily visible in wash liquor as well as against the background of the detergent formulation, therefore it is preferably coloured. Non fabric-substantive colorants may be included in the film composition at a level of 0.001 to 0.5 wt%, preferably 0.1 to 0.3 wt% of the film.
Suitable colorants include any that are used to colour detergent liquids or powders. Yellow, blue, violet, purple, red, orange, green, pink are preferred colours.
To get most effective use of their washing products many consumers soak their clothes in a solution of a laundry detergent composition. Often the clothes are placed into water, the laundry detergent composition sprinkled on top and clothes then left for 2 to 200 minutes. In this procedure, a granular laundry detergent composition may not fully dissolve and spotting of the clothes fabric with the benefit ingredients may occur. Spotting involves the incomplete dissolution of the granules and the subsequent forming of a localised high concentration of the benefit ingredient in contact with the fabric of the clothes, this highly concentrated and localised overdose of benefit ingredient may then gel and it is then inhibited from further dispersion or dissolution. This problem is most pronounced and obvious with dyes and photobleaches where clear coloured spots occur on the fabric of the clothes. The phenomenon also reduces the effectiveness of the benefit ingredients, because not all of the ingredient is made available to the full wash.
This problem is overcome by incorporating the benefit ingredients in a soluble polymer film that is then cut into discrete pieces having a low cross sectional area of less than 100mm². Such film particles also serve the purpose of visual cues since they also include dye. Their function as a visual cue may be further enhanced by cutting the film particles into the shape of a flower with petals, or some other such natural object. The cross-sectional area is at least 4mm². By cross-sectional area we mean the actual surface area of one side of the planar film particle.
The film particles have the additional advantage of keeping the often sensitive benefit ingredients away from the aggressive high pH of a base laundry detergent composition. It provides a clear visual cue to the user that the benefit ingredient is present. It is particularly desirable that the film particle floats when first added to water. This enhances the visibility of the film particle in use and can also assist with the reduction of spotting or other fabric damage due to the initial dissolution taking place on the surface, which is likely to be remote from most of the fabric being washed. To ensure that the film particle floats it is preferred that its relative density is less than 0.8, more preferably less than 0.5 and most preferably less than 0.4.
The thickness of the planar film of the film particle is at most 0.5mm. Preferably it is less than 0.3mm, most preferably 0.2mm. The film is of relatively uniform thickness to allow predictable dissolution characteristics. The thickness tolerance is at most plus or minus 20%, preferably plus or minus 10%.

SHADING DYES

The film particles comprise 0.01 to 1 wt% of a benefit ingredient selected from shading dye, for fabric whiteness.
The shading dye is selected from:

Direct dyes

Direct violet and direct blue dyes are even more preferred than pigments. Preferably, the dyes are bis or tris - azc dyes. The carcinogenic benzidene based dyes are not preferred.
Most preferably, the direct dye is a direct violet of the following structure
or
where

R₁ is hydrogen or alkyl
R₂ is hydrogen, alkyl or substituted or unsubstituted aryl, preferably phenyl
R₃ and R₄ are independently hydrogen or alkyl
X and Y are independently hydrogen, alkyl or alkoxy, preferably the dye has X= methyl and Y = methoxy.
n is 0, 1 or 2, preferably 1 or 2.

Preferred dyes are direct violet 7, direct violet 9, direct violet 11, direct violet 26, direct violet 31, direct violet 35, direct violet 40, direct violet 41, direct violet 51, and direct violet 99.
In another embodiment, the direct dye may be covalently linked to a photobleach, for example as described in WO2006/024612 .

Acid dyes

Cotton substantive acid dyes give benefits to cotton containing fabrics. Preferred dyes and mixes of dyes are blue or violet. Preferred acid dyes are:

(i) azine dyes, wherein the dye is of the following core structure:
wherein R_a, R_b, R_c and R_d are selected from: H, a branched or linear C1 to C7-alkyl chain, benzyl, a phenyl, and a naphthyl; the dye is substituted with at least one SO₃ ^- or - COO^- group; the B ring does not carry a negatively charged group or salt thereof; and the A ring may further substituted to form a naphthyl; the dye is optionally substituted by groups selected from: amine, methyl, ethyl, hydroxyl, methoxy, ethoxy, phenoxy, Cl, Br, I, F, and NO₂.
Preferred azine dyes are: acid blue 98, acid violet 50, and acid blue 59, more preferably acid violet 50 and acid blue 98.
(ii) acid violet 17, acid violet 50, acid black 1, acid red 51, acid red 17 and acid blue 29.

Hydrophobic dyes

The benefit ingredient may comprise one or more hydrophobic dyes selected from benzodifuranes, methine, triphenylmethanes, napthalimides, pyrazole, napthoquinone, anthraquinone and mono-azo or di-azo dye chromophores. Hydrophobic dyes are dyes that do not contain any charged water solubilising group. Hydrophobic dyes may be selected from the groups of disperse and solvent dyes. Blue and violet anthraquinone and mono-azo dye are preferred.
Preferred dyes include solvent violet 13, disperse violet 27 disperse violet 26, disperse violet 28, disperse violet 63 and disperse violet 77.

Basic dyes

Basic dyes are organic dyes that carry a net positive charge. They deposit onto cotton. They are of particular utility for used in composition that contain predominantly cationic surfactants. Dyes may be selected from the basic violet and basic blue dyes listed in the colour index. Preferred examples include triarylmethane basic dyes, methane basic dye, anthraquinone basic dyes, basic blue 16, basic blue 65, basic blue 66, basic blue 67, basic blue 71, basic blue 159, basic violet 19, basic violet 35, basic violet 38, basic violet 48; basic blue 3, basic blue 75, basic blue 95, basic blue 122, basic blue 124, basic blue 141.
Blue and violet thiazolium mono-azo dyes may also be used as described in WO 2007/084729 .

Reactive dyes

Reactive dyes are dyes that contain an organic group capable of reacting with cellulose and linking the dye to cellulose with a covalent bond. They deposit onto cotton. Preferably, the reactive group is hydrolysed or the dye has been reacted with an organic species such as a polymer, so as to the link the dye to this species. Dyes may be selected from the reactive violet and reactive blue dyes listed in the colour index. Examples are reactive blue 19, reactive blue 163, reactive blue 182 and reactive blue, reactive blue 96.

Dye conjugates

Dye conjugates are formed by binding direct, acid or basic dyes to polymers or particles via physical forces. Dependent on the choice of polymer or particle they deposit on cotton or synthetics. A description is given in WO2006/055787 . They may be used as benefit ingredients but are not preferred.

Example 1

A film containing the [nitrolotris(2,1-ethanediyloxy)] tris[propanol] salt of direct violet 9 was prepared as follows:

A 30% solution of polymer (Polyvinyl alcohol) and surfactant (Lauryl Ether Sulphate) are dissolved in water at 60°C.

After complete dissolution, 0.8% of the [nitrolotris(2,1-ethanediyloxy)] tris[propanol] salt of direct violet 9 is added and dissolved. This final solution is then spread as a thin layer over a glass plate of 24 x 34 cm and dried at 70-90°C in a drying oven.
After complete drying, the resulting film is taken from the glass plate and cut into the desired film particle shapes. When film particles were dissolved in water to make a 0.284 wt% solution, the solution had an optical absorption at 550 nm (1cm path length) of 0.875.

Example 2

Sodium carbonate granules containing nominally 0.1 wt% of the [nitrolotris(2,1-ethanediyloxy)]tris[propanol] salt of direct violet 9, were created by mixing an aqueous solution of the dye with sodium carbonate and drying. The dye is an effective shading agent benefit ingredient for fabric whiteness.
When granules were dissolved in water to make a 1.83 wt% solution, the solution had an optical absorption at 550 nm (1cm path length) of 0.442. Therefore, the film particle is calculated to contain 13 times more dye per weight than the granules.

Example 3

Three 3 gram samples of a washing powder were prepared. The powder contained 18 wt% sodium LAS, 73 wt% salts (silicate, sodium tripolyphosphate, sodium sulphate, sodium carbonate), remainder impurities water and minors (enzymes and fluorescer). The three samples were labelled A, B and C. To A was added 0.100g of the carbonate granule of Example 2. To B was added 0.011g of the dye benefit ingredient containing film particles of Example 1. To C was added C.084g of the film particles of Example 1. Thus, the amounts of shading dye benefit ingredient in the samples were in the ratio A:B:C of 1:1.4:11.
In Examples B and C the dye film was cut into film particles with a cross sectional area of 5 to 6 mm².
Samples were thoroughly mixed before use.
A 1.7g piece of bleached non-mereerised, white woven cotton sheeting was placed in a beaker, so that the fabric filled the bottom of the beaker in a single flat layer. To this was added 100ml of demineralised water, then sample A was sprinkled over the cloth. The solution was gently agitated for a minute then left for 5 minutes. The cloth was removed and thoroughly rinsed twice, and left to dry.
The experiment was repeated with samples B and C.
Once the cloths had dried the number of dye spots on the cloths were counted. The results are shown in table 1. Table 1

Example No. of large spots No. of small spots

A 18 106

B 0 2

C 7 3
Large spots have a diameter of greater than 1 mm. Small spots have a diameter of less than 1 mm.
Although samples B and C contain more dye than A, there is a huge redaction in spotting.

Exemplary Granular Laundry Compositions A,B,C,D

Composition	A	B	C	D
NaLAS	15	20	10	12
NI (7EO)	-	-	-	8
Na tripolyphosphate	7	15	-	-
Soap	-	-	-	1
Zeolite A24	-	-	-	17
Sodium silicate	5	4	5	1
Sodium carbonate	23	20	30	20
Sodium sulphate	40	30	40	20
Carboxymethyl cellulose	0.2	0.3	-	0.5
Percarbonate	-	3	-	10
TAED	-	0.8	-	4
Protease	0.005	0.01	-	0.005
Perfume	0.15	0.1	0.1	0.2
Perfume (petal)	0.01	-	0.03	0.05
Peal**	1	0.5	0.1	2
Amylase (petal)	0.001	0.003	-	-
Cellulase	-	0.003	-	-
Fluorescer	0.1	0.15	0.05	0.3
Direct Violet 9 (petal)	0.0002	0.0005		0.0004
Direct Violet 99	-	-	0.0003	-
Solvent Violet 13	-	0.002	-	-
Solvent Violet 13 (petal)	-	-	0.001	0.004
Food Red 14 (petal)	0.001	-	-	-
Sulfonated Zn Pthalocyanine photobleach	0.002	0.004	-	-
Water/impurities/minors	remainder	remainder	remainder	Remainder

**The petal is a film particle with cross-sectional area of 10 to 20 mm² and a film composition consisting of primary alkyl sulphate surfactant and polyvinyl alcohol polymer.

The quantity given is this line includes the minor quantities of benefit ingredients included in the film particle and identified separately by "(petal)".
Enzyme levels are given as percent pure enzyme. Levels of direct violet 9, direct violet 99, solvent violet 13 and Sulfonated Zn Pthalocyanine photobleach are given as pure dye. NI(7EO) refers to R-(OCH₂CH₂)_nOH, where R is an alkyl chain of C12 to C15, and n is 7.

Claims

A granular detergent composition comprising a plurality of film particles, each film particle comprising 5 to 50 wt% surfactant, at least 30% polyvinyl alcohol and 0.01 to 1 wt% of a benefit ingredient comprising a shading dye
characterised in that the thickness of each film particle is at most 0.5mm and the cross sectional area of each film particle is between 4mm² and 100mm².
A granular detergent composition according to claim 1 in which the film particles are rendered visible by non fabric-substantive dye that gives them a contrasting colour from the granular detergent composition.
A granular detergent composition according to claim 2 in which fluorescer and/or shading dye in the granules gives higher contrast between the granules and the film particles.
A granular detergent composition according to any preceding claim in which the composition is highly alkaline when dissolved in deionised water (0.1% solution at 25deg C is >pH 10.5 and the film particles have a pH of 3 to 9, preferably 6 to 8 when separately dissolved to form a 0.1% solution in deionised water.
A granular detergent composition according to claim 4 in which the granular detergent powder comprises silicate and/or carbonate.
A granular detergent composition according to any preceding claim in which the polymer in the film particle comprises polyvinyl alcohol.
A granular detergent composition according to any preceding claim in which the surfactant comprises at least 5 wt% anionic surfactant.
A granular detergent composition according to any preceding claim in which the film particles are made from a soluble film material that floats on the wash liquor formed by the dissolution of the granular detergent composition.