WO2006021285A1

WO2006021285A1 - Shading dyes

Info

Publication number: WO2006021285A1
Application number: PCT/EP2005/008195
Authority: WO
Inventors: Stephen Norman Batchelor; Sarah Dixon
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2004-08-25
Filing date: 2005-07-27
Publication date: 2006-03-02
Also published as: GB0418919D0; AR054080A1

Abstract

The present invention concerns the use of anthraquinone dyes ¬'or shading textiles. The anthraquinone dyds used are selected from the following structure: wherein: x is selected from the, group consisting of -OH and -NH2; R is 'seleccted from the group consisting of -CH3 and -OCH3;'' n is an integer selected from 0, 1 2 and 3; and one of the rings A, B and C is'substituted by one sulphonategroup. A laundry treatment composition comprising said anthraquinone dye and a surfactant is also claimed.

Description

SHADING DYES

FIELD OF INVENTION

The present invention relates to the use of shading dyes in laundry treatment compositions.

BACKGROUND OF INVENTION

A variety of dye types may be used for shading applications in laundry products. For example direct and acid dyes may be used, and the chromophore may be chosen from triphenyl methane, azo and anthraquinone moieties. Shading benefits function by providing a low level of colour to the white cloth, generally, blue or violet, that enhances the human perception of whiteness. A problem with the application of many shading dyes is that they build up on the cloth over multiple wash cycles giving an unacceptable high level of colour. Additionally many shading agents on cotton cloth fade rapidly when exposed to light, and the whiteness benefit is therefore lost meaning the consumer cannot enjoy the benefit through out a day of wearing. In the worst extreme the shading dye is destroyed by sunlight on line drying and the benefit is never perceived on wearing.

Shading dyes are sought that can deposit to cloth during washing whist not building up over multiple washes/treatments and exhibiting photostability over typical lengths of time for washing and wearing, e,g., several hours exposure to sunlight. SUMMARY OF INVENTION

We have found that selected dyes are particularly suitable for use in laundry treatment compositions.

In one aspect the present invention provides a laundry treatment composition comprising from 2 to 60 wt % of a surfactant and from 0.0001 to 0.02 wt % of an anthraquinone dye selected from the following structure:

wherein:

X is selected from the group consisting of -OH and -NH2 (preferably -NH2) ; R is selected from the group consisting of -CH3 and -OCH3; n is an integer selected from 0, 1 2 and 3; and one of the rings A, B and C is substituted by one sulphonate group (preferably B ring is substituted by the sulphonate) .

In another aspect of the present invention is provided a method of treating a textile with an aqueous solution of the laundry treatment composition. DETAILED DESCRIPTION OF THE INVENTION

Because the dyes are substantive, only a small amount is required to provide the enhanced whiteness effect hence the treatment composition comprises from 0.0001 to 0.02 wt%, preferably from 0.0005 to 0.01 wt% of the dye, more preferably from 0.001 to 0.01 wt%. Notwithstanding the above, the composition should be such that a "unit dose" provides a suitable dose in solution that is within- the thresholds given for the method described below. A "unit dose" as used herein is a particular amount of the laundry composition used for a type of wash. The unit dose may be in the form of a defined volume of powder, granules or tablet.

The method of the present invention employs an anthraquinone dye preferably at a concentration in the range from lOppb to 1 ppm, most preferably from lOOppb to 500ppb. The low concentration used is such that the anthraquinone dye is as such a level that the dye provides a subtle shade to a fabric rather than what would be perceived by the public as a distinct colour change.

The following is an examples of a preferred anthraquinone dye:

The use of the sodium salt of the sulphonic acid is not essential but preferred. The free acid may used but it is preferred that the anthraquinone dye is in the form of a salt.

It is preferred that the ionic strength of the aqueous laundry treatment composition is between 0.001 to 0.5, more preferably between 0.02 to 0.2. It is preferred that this ionic strength is provided by dissolution of a "unit dose" of the laundry treatment composition.

BALANCE CARRIERS AND ADJUNCT INGREDIENTS The laundry treatment composition in addition to the anthraquinone dye comprises the balance carriers and adjunct ingredients to 100 wt % of the composition.

These may be surfactants, builders, foam agents, anti-foam agents, solvents, and enzymes. The use and amounts of these components are such that the composition performs depending upon economics, environmental factors and use of the composition. The composition may comprise a surfactant and optionally- other conventional detergent ingredients. The composition may also comprise an enzymatic detergent composition which comprises from 0.1 - 50 % by weight, based on the total detergent composition, of one or more surfactants. This surfactant system may in turn comprise 0 - 95 % by weight of one or more anionic surfactants and 5 to 100 % by weight of one or more nonionic surfactants. The surfactant system may additionally contain amphoteric or zwitterionic detergent compounds, but this in not normally desired owing to their relatively high cost. The enzymatic detergent composition according to the invention will generally be used as a dilution in water of about 0.05 to 2%.

It is preferred that the composition comprises between 2 to 60 wt % of a surfactant. In general, the nonionic and anionic surfactants of the surfactant system may be chosen from the surfactants described "Surface Active Agents" Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon' s Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are C₆-C₂₂ alkyl phenol-ethylene oxide condensates, generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C₈- C18 primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 40 EO.

Suitable anionic detergent compounds which may be used are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals. Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher Cg-Cis alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl C₉-C₂₀ benzene sulphonates, particularly sodium linear secondary alkyl C₁₀-C₁₅ benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum. The preferred anionic detergent compounds are sodium C₁₁-C₁₅ alkyl benzene sulphonates and sodium C₁₂-C_3.8 alkyl sulphates. Also applicable are surfactants such as those described in EP-A-328 177 (Unilever) , which show resistance to salting-out, the alkyl polyglycoside surfactants described in EP-A-070 074, and alkyl monoglycosides.

Preferred surfactant systems are mixtures of anionic with nonionic detergent active materials, in particular the groups and examples of anionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever) . Especially preferred is surfactant system that is a mixture of an alkali metal salt of a C₁6-C₁8 primary alcohol sulphate together with a C₁2-C₁₅ primary alcohol 3-7 EO ethoxylate.

The nonionic detergent is preferably present in amounts greater than 10%, e.g. 25-90% by weight of the surfactant system. Anionic surfactants can be present for example in amounts in the range from about 5% to about 40% by weight of the surfactant system.

Cationic Compound

When the present invention is used as a fabric conditioner it needs to contain a cationic compound.

Most preferred are quaternary ammonium compounds.

It is advantageous if the quaternary ammonium compound is a quaternary ammonium compound having at least one C12-C22 alkyl chain. '

It is preferred if the quaternary ammonium compound has the following formula:

R²

R¹ - N⁺ - R^J X^"

R⁴

in which R¹ is a C12 to C₂₂ alkyl or alkenyl chain; R², R³ and R⁴ are independently selected from C₁-C₄ alkyl chains and X^" is a compatible anion. A preferred compound of this type is the quaternary ammonium compound cetyl trimethyl quaternary ammonium bromide.

A second class of materials for use with the present invention are the quaternary ammonium compound having the following formula:

R'

R¹ - N⁺ - R³ X^"

R^q

in which R¹ and R² are independently selected from C12 to C₂₂ alkyl or alkenyl chain; R³ and R⁴ are independently selected from C₃.-C₄ alkyl chains and X^~ is a compatible anion.

A detergent composition according to claim 1 in which the ratio of (ii) cationic material to (iv) anionic surfactant is at least 2:1.

Other suitable quaternary ammonium compounds are disclosed in EP 0 239 910 (Proctor and Gamble) .

It is preferred if the ratio of cationic to nonionic surfactant is from 1:100 to 50:50, more preferably 1:50 to 20:50.

The cationic compound may be present from 0.02 wt% to 20 wt% of the total weight of the composition.

Preferably the cationic compound may be present from 0.05 wt% to 15 wt%, a more preferred composition range is from 0.2 wt% to 5 wt%, and most preferably the composition range is from 0.4 wt% to 2.5 wt% of the total weight of the composition. If the product is a liquid it is preferred if the level of cationic surfactant is from 0.05wt% to 10wt% of the total weight of the composition. Preferably the cationic compound may be present from 0.2 wt% to 5 wt%, and most preferably from 0.4 wt% to 2.5 wt% of the total weight of the composition.

If the product is a solid it is preferred if the level of cationic surfactant is 0.05 wt% to 15 wt% of the total weight of the composition. A more preferred composition range is from 0.2 wt% to 10 wt%, and the most preferred composition range is from 0.9 wt% to 3.0 wt% of the total weight of the composition.

BLEACHING SPECIES

The laundry treatment composition may comprise bleaching species. The bleaching species, for example, may selected from perborate and percarbonate. These peroxyl species may be further enhanced by the use of an activator, for example, TAED or SNOBS. Alternatively or in addition to, a transition metal catalyst may used with the peroxyl species. A transition metal catalyst may also be used in the absence of peroxyl species where the bleaching is termed to be via atmospheric oxygen, see, for example WO02/48301. Photobleaches, including singlet oxygen photobleaches, may be used with the laundry treatment composition. A preferred photobleach is vitamin K. EXPERIMENTAL

Example 1 - Dye substantivity

To determine the substantivity of a range of dyes the following experiment was performed. A stock solution of 1.5g/L of a base washing powder in water was created. The washing powder contained 18% NaLAS, 73% salts (silicate, sodium tri-poly-phosphate, sulphate, carbonate) , 3% minors including perborate, fluorescer and enzymes, remainder impurities and water. The solution was divided into 60ml aliquots and dye added to this to give a solution of optical density of approximately 1 (5 cm pathlength) at the maximum absorption of the dye in the visible lengths, 400-700nm. The optical density was measured using a UV-visible spectrometer. One piece of bleached, non-mercerised, non- fluorescent woven cotton cloth (ex Phoenic Calico) weighing 1.3g was placed in the solution at room temperature (20⁰C) . This cloth represents a slightly yellow cotton. The cloth was left to soak for 45 minutes then the solution agitated for 10 mins, rinsed and dried. Following this the optical density of the solution was re-measured and the amount of dye absorbed by the cloth calculated. This experiment was repeated for each dye and the results provided in the table below.

It is most preferred that the dyes of the present invention meet this standard test having a substantivity of greater than 8%. The test as disclosed above may be genericised as follows: a solution of dye being prepared such that the solution has (i) an optical density of 1 (5 cm pathlength) at the maximum absorption of the dye in the visible wavelengths, (ii) a sodium lauryl alkyl benzene sulphonate surfactant concentration of 0.3 g/1, (iii) inorganic non- surfactant salt concentration of 1.1 g/1, (iv) under wash conditions of a liquor to cloth ratio of 45:1, temperature of 20°C, soak times of 45 minutes, and an agitation time of 10 minutes.

A wide range of dyes may deposit to cotton. Within the anthraquinone dyes acid blue 25 shows a high level (>10%) of deposition.

Example 2: Build-up on non-mercerised cotton The build up of the dyes of Example 1 over multiple washes was followed by monitoring the dye level on non-mercerised cotton cloth by reflectance spectroscopy. The results showed that the acid dyes did not build up over multiple washes but reached a plateau loading value on cotton. However for the direct dyes the dye loading on cloth (in g/kg) increased linearly with wash number.

Example 3 - Dye Photofading

Non-mercerised cotton cloth was dyed with the dyes listed in the table below. The dying was done from a wash solution containing the washing powder described in example 1 with dye added to solution to give a similar level of colour on the cloth (measured as the Delta E value relative to undyed cloth) . Following the dying the photostability of the dyes on cotton was investigated by irradiating the cloth for 5 hours in a weatherometer set to give 385 W/m² in the UV- visible range. The Delta E of the cloth was then remeasured, if the value had greatly dropped then the dye has been substantially photofaded.

The anthraquinone dye has a far superior photostability on cotton than the azo or triphenylmethane dyes.

Claims

aim :

A laundry treatment composition comprising from 2 to 60 wt % of a surfactant and from 0.0001 to 0.02 wt % of an anthraquinone dye selected from the following structure:

wherein:

X is selected from the group consisting of -OH and -

NH2;

R is selected from the group consisting of -CH3 and -

OCH3; n is an integer selected from 0, 1 2 and 3; and one of the rings A, B and C is substituted by one sulphonate group, wherein the dye has a substantivity to non-mercerised cotton in a standard test of at least 8% and wherein the standard test involves a solution of dye being prepared such that the solution has (i) an optical density of 1 (5 cm pathlength) at the maximum absorption of the dye in the visible wavelengths, (ii) a sodium lauryl alkyl benzene sulphonate surfactant concentration of 0.3 g/1, (iii) inorganic non- surfactant salt concentration of 1.1 g/1, (iv) under wash conditions of a liquor to cloth ratio of 45:1, temperature of 20°C, soak times of 45 minutes, and an agitation time of 10 minutes.

2. A laundry treatment composition according to claim 1, wherein X is -NH2.

3. A laundry treatment composition according to claim 1, wherein X is -OH.

4. A laundry treatment composition according to claim 1, wherein the anthraquinone dye is:

A laundry treatment composition according to claim 1, wherein the anthraquinone dye is:

(Acid violet 43)

A laundry treatment composition according to any preceding claim, wherein the laundry treatment composition is a fabric conditioning composition.

A laundry treatment composition according to one of claims 1 to 5, wherein the laundry treatment composition is a detergent washing composition.

A method of treating a textile, the method comprising the steps of:

(i) treating a textile with an aqueous solution of an anthraquinone dye selected from the following structure:

wherein: X is selected from the group consisting of -OH and - NH2;

R is selected from the group consisting of -CH3 and OCH3; n is an integer selected from 0, 1 2 and 3; and one of the rings A, B and C is substituted by one sulphonate group.

9. A method according to claim 8, wherein the anthraquinone dye is selected from:

10. A method of treating a textile according to claim 8 or 9, wherein the anthraquinone dye is present in solution at a concentration in the range from lOppb to 1 ppm.

11. A method of treating a textile according to any one of claims 8 to 10, wherein the ionic strength of the solution is in the range from 0.001 to 0.5.