WO2007096068A1

WO2007096068A1 - Liquid whitening maintenance composition

Info

Publication number: WO2007096068A1
Application number: PCT/EP2007/001169
Authority: WO
Inventors: Stephen Norman Batchelor; Jayne Michelle Bird; Carol Meacock; Dawn Rigby; Jacqueline Willaims
Original assignee: Unilever Plc; Unilever Nv; Hindustan Unilever Limited
Priority date: 2006-02-24
Filing date: 2007-02-07
Publication date: 2007-08-30
Also published as: AR059606A1; EP1987124B1; EP1987123A1; EP1987124A1; WO2007096067A1

Abstract

The present invention provides an aqueous laundry liquid detergent formulation comprising an anthraquinone hydrophobic dye, a surfactant mixture, comprising a non-ionic surfactant and an anionic surfactant and a fluorescent agent. The precipitation of the dye is reduced.

Description

LIQUID WHITENING MAINTENANCE COMPOSITION

FIELD QF INVENTION

The present invention concerns maintaining sort chain non- charged dyes in a laundry liquid composition and reducing precipitation thereof in combination with increased deposition of the dye to a substrate.

BACKGROUND OF INVENTION

US 4,800,037 and US 4,110,238 disclose the use of solvent blue 58, a hydrophobic anthraquinone dye containing a C8 chain at levels of 0.005 to 0.025 wt % in a laundry liquid formulation. The long alkyl chain, i.e. the C8 , helps to solubilise the dye in the liquid formulation. The long chain effectively interacts with the alkyl chains of the surfactant reducing precipitation of the dye over time. Additionally, the formulation also contains a hydrotrope to solubilise the dye. Solvent blue 58 is of the following

structure :

JP 2004/210961, to Lion Corporation, discloses the use of anthraquinone dyes in a liquid detergent composition purely for enhancing the aesthetic appearance of the liquid detergent composition. The compositions comprise alkanolamine, an anionic surfactant and a non-ionic surfactant. In all the examples in JP 2004/210961 alcohol is present as a solubilising agent for the dye, i.e., 5 wt % of ethanol is present. In some of the examples propylene glycol is also present to facilitate solubility of the dye.

SUMMARY OF THE INVENTION

We have found that by formulating a liquid detergent with differing surfactants with specific ratios the requirement of a long chain, i.e., C8 or greater, to stabilise the formulation is not necessary. This permits a greater selection of dyes that may be used in the liquid detergent formulation.

We have also found a synergy between dyes and fluorescent agents. The fluorescent agents aid deposition of the dye.

Shading dyes impart a colour to a textile. The dyes are substantive to the textile and preferably are blue of violet in order to give a perception of whiteness. This perception of whiteness is of importance as textile clothing ages. Hydrophobic dyes are used to shade synthetic garments.

For main wash liquid detergent formulations that contain shading dyes, the shading dye need to remain solubilised as best as possible in the liquid formulation from the time of production to the time of use in the home. Even in the presence of surfactants hydrophobic dyes precipitate from solution with time. The liquid formulations of the present invention reduce this precipitation.

In one embodiment the present invention provides an aqueous laundry liquid detergent formulation comprising:

(a) from 0.000001 to 0.01% of a hydrophobic dye

(b) from 10 to 50 wt% of a surfactant mixture, the surfactant mixture comprising: (i) a non-ionic surfactant; and (ii) a anionic surfactant selected from the group consisting of: linear alkyl benzene sulphonate, alkyl sulphate, and alkyl ethoxylated sulphate,

(c) from 0.005 to 2 wt% of a fluorescent agent selected from: sodium 2 (4-styryl-3 -sulfophenyl) -2H-napthol [1 , 2- djtriazole, disodium 4 , 4 ' -bis{ [ (4-anilino-6- (N methyl-iV- 2 hydroxyethyl) amino 1 , 3 , 5-triazin-2- yl) ] amino}stilbeno-2-2 ' disulfonate, disodium 4,4'- bis [ (4-anilino-6-morpholino-l ,3,5-triazin-2-yl) amino] stilbene-2-2 ' disulfonate, and disodium 4,4 '-bis (2- sulfostyryl) biphenyl , and,

(d) the balance adjuncts to 100 wt %, wherein the ratio of anionic surfactant to non- ionic surfactant is in the range from 0.5 to 1.5:1 and one of the selected anionic surfactants is present in 85 wt% excess of the total anionic surfactant content, wherein the hydrophobic dye is an anthraquinone dye of the following structure (I) :

wherein Rl, R4 , R5 , and R8 are independently selected from the groups consisting of -H, -OH, -NH₂, -NHR9, and -NO₂, such that a maximum of only one -N02 group and a maximum of two - H are present as Rl, R4 , R5 , and R8 substituents; where R9 is an branched or linear Cl-C7-alkyl chain or an aryl group or substituted aryl groups, or a branched or linear Cl-C7-alkyl chain, the branched or linear Cl-C7-alkyl chain is preferably not substituted by an -OH group or -OMe; R2, R3, R6, and R7 may be selected from -H, -F, -Br, -Cl, SO3aryl or -NO₂, and -ORlO, wherein RlO is selected from the group consisting of branched or linear Cl-C7-alkyl or aryl ; and, R2 and R3 may together be joined to form a five membered non-aromatic ring of the form -C (=0) N (HRIl) C (=X) - , wherein X is 0 or NH and RIl is selected from the group consisting of Cl-C6-alkyl optionally substituted with alkoxy groups .

Furthermore, in a second aspect the invention provides a method of treating textile, comprising the steps of: a) diluting from 0.5 to 20 g of the liquid detergent formulation according to the present invention with 1 litre of water to form a diluted composition; b) treating the textile with the diluted composition; c) rinsing the textile with water; and d) drying the textile.

Treatment is preferably carried out in the domestic context, at temperature between 10 to 60 ⁰C, preferably 15 to 40 ⁰C.

DETAILED DESCRIPTION OF THE INVENTION

The water present in the aqueous laundry liquid detergent formulation is preferably at a level of at least 40 wt%.

Preferably the selected anionic surfactant is present in 99 wt% excess of the total anionic surfactant content.

Preferably ratio of anionic surfactant to non- ionic surfactant is in the range from 0.75 to 1:1.

Preferably the dye level is in the range from 0.0002 to 0.004%.

All percentages and ratios are expressed with respect to weight .

We have found that alcohols are not necessary to stabilise the formulation. In this regard, it is preferred that the aqueous laundry liquid detergent formulation has less than 0.5 wt %, more preferably less than 0.05 wt% of a Cl to C4 alcohol or polyol .

We have found that alkanolamines are also not necessary to stabilise the formulation. In this regard, it is preferred that the aqueous laundry liquid detergent formulation has less than 0.05 wt %, more preferably less than 0.005 wt% of an alkanolamines .

SURFACTANT

The liquid composition of the invention comprises from 10 to 50 wt%, preferably from 12 to 25 % by weight of a surfactant mixture .

Linear alkyl benzene sulphonates salts (LAS) , particularly Ci_I-Ci₈ alkylbenzene sulphonates in the form of the sodium salt.

Alkyl sulphate surfactants are either primary or secondary. Alkyl sulphates have the general formula ROSO₃M wherein R is preferably a Ci_O-C₂₄ hydrocarbyl, preferably an alkyl straight or branched chain or hydroxyalkyl having a Ci₀-C_2O alkyl component, more preferably a Ci₂-Ci₈ alkyl or hydroxyalkyl, and M is hydrogen or a water soluble cation, e.g., an alkali metal cation (e.g., sodium potassium, lithium) . Particularly preferred is sodium dodecyl sulphate (SDS) .

Alkyl ethoxylated sulphate surfactants are another category of preferred anionic surfactant. These surfactants are water soluble salts or acids typically of the formula RO (A) mS0₃M wherein R is an unsubstituted Ci₀-C₂₄ alkyl or hydroxyalkyl group having a Ci₀-C₂₄ alkyl component, preferably a Ci₂-C₂₀ alkyl or hydroxyalkyl, more preferably Ci₂-Ci₈ alkyl or hydroxyalkyl, A is an ethoxy, m is greater than zero, typically between about 1 and 6, more preferably between 1 and 3, and M is hydrogen or a water soluble cation which can be, for example, a metal cation (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted- ammonium cation. Exemplary surfactants are Ci₂-Ci₈ alkyl polyethoxylate (1.0) sulphate, C_i2- Ci₈ alkyl polyethoxylate .(2.25) sulphate, C₁₂-Ci₈ alkyl polyethoxylate (3.0) sulphate, and C₁₂-Ci₈ alkyl polyethoxylate (4.0) sulphate wherein M is conveniently selected from sodium and potassium. With respect to the above, propoxylated sulphates may also be used. Sodium lauryl ether sulphates are most preferred with one to three ethoxy groups.

Non-ionic surfactant, particularly alcohol ethoxylates, R- (OCH₂CH₂) _nOH, where R is an alkyl chain typically ClO to C18, preferably C12 to C15, and n is 3 to 20, preferably 7 to 9, most preferred n = 9. Other non- ionic surfactant may be selected from C₆-Ci₂ alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy) , block alkylene oxide condensate of C₆ to C₁₂ alkyl phenols, alkylene oxide condensates of C₈-C₂₂ alkanols and ethylene oxide/propylene oxide block polymers (Pluronic™-BASF Corp.) .

Further minor surfactants may be added include cationics, soaps, betaines, alkylpolyglycosides, N-methyl glucomides . It is preferred that the minor surfactants are present at levels below 3 wt%.

THE HYDROPHOBIC DYE

Typical dye suppliers may be found in the colour index, and include Clariant, Dystar, Ciba & BASF. Hydrophobic dyes are defined as organic compounds with a maximum extinction coefficient greater than 1000 L/mol/cm in the wavelength range of 400 to 750 nm and that are uncharged in aqueous solution at a pH in the range from 7 to 11. The hydrophobic dyes are devoid of polar solubilising groups. In particular the hydrophobic dye does not contain any sulphonic acid, carboxylic acid, or quaternary ammonium groups .

Many examples of hydrophobic dyes are found in the classes of solvent and disperse dyes . Mixtures of dyes may be used in the present invention.

Shading of white garments may be done with any colour depending on consumer preference. Blue and Violet are particularly preferred shades and consequently preferred dyes or mixtures of dyes are ones that give a blue or violet shade on white polyester.

It is preferred that the dye(s) have a peak absorption wavelength of from 550nm to 650nm, preferably from 570nm to 630nm. A combination of dyes may be used which together have the visual effect on the human eye as a single dye having a peak absorption wavelength on polyester of from 550nm to

650nm, preferably from 570nm to 630nm. This may be provide for example by mixing a red and green-blue dye to yield a blue or violet shade.

A wide range of suitable solvent and disperse dyes are available. However detailed toxicological studies have shown that a number of such dyes are possible carcinogens, such dyes are not preferred.

The anthraquinone dye used in the present invention does not have any single alkyl substituent, branched or linear, of more than C7. Preferably the anthraquinone dye used in the present invention does not have single any alkyl substituent, branched or linear, of more than C5. Most preferably the anthraquinone dye used in the present invention does not have single any alkyl substituent, branched or linear, of more than C2.

It is preferred that if R9 and/or RlO is a branched or linear alkyl chain then the chain has less than six carbon atoms and does not have an OH or OMe substituent .

It is preferred that the R9 and RlO are not branched or linear alkyl chains; R9 and RlO may be methyl, i.e., not a chain. It is preferred that R2 and R3 are individual substituents and are not covalently bound together to form a ring. In particular, It is preferred that R2 and R3 are not joined to form a five membered non-aromatic ring of the form -C (=0) N (HRIl) C (=X) -, wherein X is 0 or NH and RIl is selected from the group consisting of Cl-C6-alkyl optionally substituted with alkoxy groups.

It is preferred that Rl, R4 , R5 , and R8 are independently selected from the groups consisting of -H, -OH, -NH₂, and - NO₂, and R2 , R3 , R6 , and R7 is selected from -H, F, Br, Cl or -NO₂, and -Oaryl . It is also preferred that the aryl is an optionally substituted phenyl. Of the Rl, R4 , R5 and R8 it is most preferred that is -OH and one is selected from -NH2 and -NHR9.

It is preferred that R2 , R3 , R5 , R6 , R7 , and R8 are -H, Rl = -OH, R4 = -NHR9 or -NH2.

It is preferred that R5 , R6 , R7 , and R8 = -H, Rl = R4 = - NH2, R2 = R3 = -Oaryl, or -Cl.

Most preferred dyes are disperse blue 56, solvent violet 13, disperse violet 26 and disperse violet 28.

It is preferred that disperse blue 87 and disperse blue 7 are excluded from the hydrophobic dye of the anthraquinone structure.

The composition may also comprise between 0.0001 to 0.1 wt % of one or more other dyes selected from cotton substantive shading dyes of group consisting of : hydrolysed reactive dye,- acid dye; and direct dye. Example of preferred acid dyes are: acid blue 62, 40 and 290.

BALANCE ADJUNCTS OF THE LIQUID FORMULATION

Preferably the aqueous liquid detergent formulation has a pH-value between 6 and 12, more preferably between 7 and 10, even more preferably between 7.5 and 9.5. When the pH-value of the detergent composition of the invention is below 7.5, the presence of a pH jump system, i.e. a system that increase the pH-value to above 7.5 on dilution with water, is beneficial for the cleaning performance of said composition.

The liquid detergent composition of the invention may additionally comprise builders, solvents, perfumes, sequestrants, polymers, preservatives, fluorescers, dyes, biocides, buffers, salts.

Suitable detergency builders as optional, but preferred, ingredients may also be present, as found in WO-00/34427. One salt of particular interest is citrate, because of its additional builder and bleaching characteristics.

The following are also preferred adjuncts.

PERFUMES

The liquid formulation of the present invention preferably comprises between 0.001 to 3% by weight of a perfume composition, more preferably between 0.1 to 2% by weight of a perfume composition. Said perfume composition preferably comprises at least 0.01% by weight based on the liquid composition of a perfume component selected from terpenes, ketones, aldehydes and mixtures thereof. The perfume composition may fully consist of the perfume component but generally the perfume composition is a complex mixture of perfumes of various differing perfume classifications. In this regard, the perfume composition preferably comprises 0.1 to 2% by weight of the perfume component. ANTIOXIDANT

The liquid detergent composition of the invention preferably comprise between 0.001 to 2% by weight of an antioxidant. Preferably, the antioxidant is present at a concentration in the range 0.01 to 0.08% by weight. Anti-oxidants are substances as described in Kirk-Othmers (VoI 3, pg 424) and in Uhlmans Encyclopedia (VoI 3, pg 91) . An example of a preferred antioxidant is BHT.

FLUORESCENT AGENT

The laundry treatment composition comprises a fluorescent agent (optical brightener) . We have found that the presence of a fluorescent agent enhances the deposition of the dye. Fluorescent agents are well known and many such fluorescent agents are available commercially. Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in laundry treatment composition is from 0.005 to 2 wt %, more preferably 0.01 to 0.1 wt %. Preferred fluorescers are: sodium 2 (4-styryl-3-sulfophenyl) -2H-napthol [1 , 2-d] triazole, disodium 4 , 4 ' -bis{ [ (4-anilino-6- (N methyl-N-2 hydroxyethyl) amino 1 , 3 , 5-triazin-2-yl) ] amino}stilbeno-2-2 ' disulfonate, disodium 4,4 ' -bis [ (4-anilino-6-morpholino-l, 3,5-triazin-2- yl) amino] stilbene-2-2 ' disulfonate, and disodium 4,4'- bis (2-sulfostyryl) biphenyl . Examples

Model Liquid detergent composition were created containing 15% total surfactant and 0.0004% of the dye solvent violet 13. The surfactants were chosen from LAS, SDS, SLES(IEO), SLES (3EO), and two non-ionic surfactants: non-ionic NI (7EO) - Neodol 25-7 which is a mixture of 12 to 15 carbon chain length alcohols with about 7 ethylene oxide groups per molecule and NI (9EO) - Neodol 25-9, a C12-13 mixture with about 9 moles of ethylene oxide.

The dye was added from a concentrated mix in the corresponding non- ionic of the formulation. The detergents were left for 5 days then the UV-VIS spectrum measured using a 5cm cell. The optical density at 590nm was recorded (maximum of the dye) and 750nm where there is negligible absorbance from the dye. The base surfactant has negligible absorbance at 590 and 750nm. The 750nm was made to measure scattering from dye particles that were not fully dissolved. These measurements are referred to as day 0.

The formulations were left at room temperature in the dark for 8 days then the spectra re-recorded. The relative amount of dye that remain solubilised in solution compared to the initial measurement, %dye8, was calculated using the following equation:

%dye8 = 100* [OD (590nm, day 8) - OD (750 nm, day 8)]

[OD(590nm, day 0) - OD (750 nm, day O)]

The 750nm subtraction corrects for scattering effects. The results are summarised in the tables and discussions below. The values greater than 100% indicate that with time more dye becomes solubilised.

Table 1.1 binary mixtures of non-ionic/anionic surfactants.

The results from Table 1.1 show that binary mixtures of anionic and non-ionic surfactant effectively solubilise the dye over long periods of time.

Table 1.2 mixtures of LAS or SDS with non-ionic containing low levels of SLES.

The table shows that mixtures of LAS or SDS with non- ionic containing low levels of SLES, effectively solubilise the dye over long periods of time. NI (9EO) containing mixtures performed better over NI (7EO) .

Table 1.3 mixtures of LAS or SDS with non- ionic containing medium levels of SLES.

Surfactant mix %dye8

6% LAS, 6% NI (9EO) , 3% SLES (3EO) 76%

6% LAS, 6% NI (7EO) , 3% SLES (3EO) 82%

6% SDS, 6% NI (9EO) , 3% SLES (3EO) 81%

6% SDS, 6% NI (7EO) , 3% SLES (3EO) 75%

The table shows that mixtures containing SLES (3E0) do not effectively solubilise the dye over long period of time.

Table 1.4 mixtures of SLES and non-ionic with medium levels of LAS or SDS .

Example 2

Fully formulated wash products were created containing the following by weight: Formula 1 [7% SLES (3EO); 7% NI (7EO) ; 1.5% fatty acid; 1% cationic surfactant; 1% sequestrant dequest 2066; 0.2% NaOH; 0.005% Solvent Violet 13; less than 2.5% minors including fluorescer, boric acid, NaCl, perfume, propylene glycol, enzymes; remainder water] .

Formula 2 [10% LAS; 10% NI(OEO); 4% alkalinity and stabilizers; 3% sodium silicate; 0.005% solvent violet 13; <2% minors; remainder water] .

The UV-Vis spectrum was measured once the products were created, and then after 5 weeks storage in sealed containers in the dark at room temperature. No loss of dye was observed.

Example 3

When the liquid formulations of example 1 and example 2 were used to wash white polyester, nylon and nylon elastane fabrics at room temperature with a dose 1.8g/L and a L: C of 100:1, clear deposition of the dye to the fabrics was observed giving better whiteness. This occurred when the product was buffered to pH 8 and pH 11.

Example 4 The following detergent liquid formulation were created:

(a) 15% surfactant (1:1 LAS :NI (7EO) ) , remainder water

(b) 15% surfactant (1:1 LAS :NI (7EO) ) , 0.005% solvent violet 13, remainder water

(c) 15% surfactant (1:1 LAS :NI (7EO) ) , 0.1% Tinopal DMS-X, remainder water (d) 15% surfactant (1:1 LAS :NI (7EO) ) , 0.1% Tinopal DMS-X, 0.005% solvent violet 13, remainder water

The formulations were separately used to wash woven polyester for 30 minutes at room temperature, with 2g/L formulation and a liquor to cloth ratio of 30:1. Following the wash the clothes were rinse, dried and the reflectance spectra recorded with UV excluded.

The spectrum of (a) and (d) were identical as would be expected. The reflectance spectra showed clear deposition of solvent violet 13 for (b) and (d) . The presence of the fluorescer in (d) gave an increased deposition of solvent violet 13 of 140% (2 significant figures) over (b) .

Tinopal DMS is

Example 5

The experiment of example (4) was repeated except Tinopal CBS was used as the fluorescer and the surfactant system was SDS:NI(9EO). The fluorescer/solvent violet 13 formulation gave 130% more deposition of solvent violet 13 then the formulation with solvent violet 13 alone.

Claims

We claim :

1. An aqueous laundry liquid detergent formulation comprising : (a) from 0.000001 to 0.01% of a hydrophobic dye

(b) from 10 to 50 wt% of a surfactant mixture, the surfactant mixture comprising: (i) a non- ionic surfactant; and (ii) a anionic surfactant selected from the group consisting of: linear alkyl benzene sulphonate, alkyl sulphate, and alkyl ethoxylated sulphate,

(c) from 0.005 to 2 wt% of a fluorescent agent selected from: sodium 2 (4-styryl-3-sulfophenyl) -2H-napthol [1 ,

2- djtriazole, disodium 4 , 4 ' -bis{ [ (4-anilino-6- {N methyl-N- 2 hydroxyethyl) amino 1 , 3 , 5-triazin-2- yl) ] amino}stilbeno-2-2 ' disulfonate, disodium 4,4'- bis [ (4-anilino-6-morpholino-l ,3,5-triazin-2-yl) amino] stilbene-2-2 ' disulfonate, and disodium 4,4 '-bis (2- sulfostyryl) biphenyl, and, (d) the balance adjuncts to 100 wt %, wherein the ratio of anionic surfactant to non- ionic surfactant is in the range from 0.5 to 1.5:1 and one of the selected anionic surfactants is present in 85 wt% excess of the total anionic surfactant content, wherein the hydrophobic dye is an anthraquinone dye of the following structure (I) :

wherein Rl, R4 , R5 , and R8 are independently selected from the groups consisting of -H, -OH, -NH₂, -NHR9, and -NO₂ , such that a maximum of only one -N02 group and a maximum of two -H are present as Rl, R4 , R5 , and R8 substituents ; where R9 is an branched or linear Cl-C7-alkyl chain or an aryl group or substituted aryl groups, or a branched or linear Cl-C7-alkyl chain, the branched or linear Cl- C7-alkyl chain is preferably not substituted by an -OH group or -OMe; R2 , R3 , R6 , and R7 may be selected from -H, -F, -Br, -Cl, SO3aryl or -NO₂, and -ORlO, wherein RlO is selected from the group consisting of branched or linear Cl-C7-alkyl or aryl; and, R2 and R3 may together be joined to form a five membered non-aromatic ring of the form -C (=0) N (HRIl) C (=X) - , wherein X is 0 or NH and RIl is selected from the group consisting of Cl- C6-alkyl optionally substituted with alkoxy groups.

An aqueous laundry liquid detergent formulation according to claim 1, wherein with respect to the selected anionic surfactant is present in 99 wt% excess of the total anionic surfactant content .

3. An aqueous laundry liquid detergent formulation according to claim 1 or 2 , wherein the ratio of anionic surfactant to non- ionic surfactant is in the range from 0.75 to 1:1.

4. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein the non- ionic is an alcohol ethoxylate, the alkyl ethoxylated sulphate is a sodium lauryl ether sulphate, and the alkyl sulphate is sodium dodecyl sulphate.

5. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein the non- ionic is selected from alcohol ethoxylate containing a carbon chain of 12 to 15 carbons and 7 to 9 ethylene oxide groups .

6. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein the alcohol ethoxylate contains 9 ethylene oxide groups.

7. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein the hydrophobic dye is blue or violet.

8. An aqueous laundry liquid detergent formulation according to claim 7, wherein the hydrophobic dye is selected from solvent violet 13, disperse blue 56, disperse violet 26 and disperse violet 28.

9. An aqueous laundry liquid detergent formulation according to claim 7, wherein dye is solvent violet 13.

10. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein the dye level is in the range from 0.0002 to 0.004%.

11. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein the surfactant mixture is present in the range 12 to 25 wt%.

12. An aqueous laundry liquid detergent formulation according to any preceding claim, wherein a surfactant other than defined in claim 1 is present at a levels of less than 3 wt%.