EP2813564A1

EP2813564A1 - Laundry formulation comprising a dye

Info

Publication number: EP2813564A1
Application number: EP13171971.8A
Authority: EP
Inventors: Stephen Norman Batchelor; Jane Michelle Bird; Neil Stephen Burnham; Martin Charles Crossman; Francesca Topi
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 2013-06-14
Filing date: 2013-06-14
Publication date: 2014-12-17

Abstract

The present invention provides a laundry liquid composition with enhanced storage stability comprising a dye, the dye being covalently linked to a chain containing an ester group with a carboxylic acid group on the beta carbon to the ester, the composition having a dilution pH in the range from 6.1 to 6.9.

Description

FIELD OF INVENTION

The invention concerns formulations with dyes.

BACKGROUND OF THE INVENTION

WO2012/166768 (Procter & Gamble) discloses a laundry formulation containing an azo dye covalently linked to a polymer chain, wherein the polymer chain contains an ester group with a carboxylic acid group on the β carbon. The dye decomposes on storage in liquid detergents.

SUMMARY OF THE INVENTION

Surprisingly it is found if the pH of the liquid detergent is from pH 6.1 to 6.9 less decomposition of the dye occurs.
In one aspect the present invention provides a laundry liquid composition comprising: from 0.0001 to 1wt% of a dye, the dye covalently linked to a polymer chain(s), wherein the polymer chain contains an ester group with a carboxylic acid group on the β carbon to the ester group and the laundry liquid composition comprises from 1 to 80 wt% water and the laundry liquid composition having a dilution pH in the range from 6.1 to 6.9, preferably 6.2 to 6.7, most preferably 6.4 to 6.6, wherein the dilution pH is measured by adding 10 g of the laundry liquid composition into 40 g of pH neutral demineralised water and the pH measured at 293 K.
Preferably the composition comprises from 2 to 70 wt% of a surfactant; most preferably the surfactant comprises from 50 to 100 wt % anionic surfactant.

DETAILED DESCRIPTION OF THE INVENTION

The dye is preferably blue or violet in colour in aqueous solution. In aqueous solution, they preferably have an optical absorption maximum in the visible of 550 to 600 nm, more preferably 560 to 590nm. This is measured using a UV-VIS spectrometer in aqueous solution.
The dye has a maximum molar extinction coefficient at a wavelength in the range 400 to 700nm of at least 30 000 mol^-1 L cm^-1, preferably greater than 50000 mol^-1 L cm^-1.
Preferably the dye has a molecular weight from 500 to 2000, most preferably 800 to 1200.
Dye weights refer to the sodium salts unless otherwise stated.
The laundry liquid composition can be a whole laundry composition or part of a laundry composition as found in unit dose capsules-laundry liquid unit dose. Unit dose capsules may have a plurality of compartments as found, for example, in P&G's PODS^™ product. PODS^™ have three compartments. The laundry liquid composition containing the dye may be extracted from a single compartment for testing.
Preferably the polymer chain(s) is/are polyoxyalkylene chain(s) have from 2 to 10 repeating units; more preferably the polyoxyalkylene chain(s) have from 2 to 10 repeating units is/are polyoxyethylene chain(s).
Preferably the dye is of the form selected from:
wherein R₁ and R₂ are independently selected from H, C1-C20 alkyl and C3-C20 alkylene and integer n takes values from 1 to 9 and integer m takes values from 0 to 9. Preferably, R₁ and/or R₂ is/are C3-C20 alkylene, wherein the alkylene contains one carbon-carbon trans double bond starting 3 carbons removed from the carboxylic acid.
For the avoidance of doubt the β carbon to the ester group and the 3 position of the carbon-carbon double bond are shown below
The dye chromophore is preferably selected from mono-azo, bis-azo, triphenylmethane and anthraquinone. Preferably the dye is a mono-azo dye. Most preferably the dye is a mono-azo thiophene dye.
Preferably the dye selected from:
and,
wherein integer n takes values from 1 to 9 and integer m takes values from 0 to 9.
Preferred values of n and integer m are n = 2, 3, 4 and m = 2, 3, 4.

Surfactant

In general, the 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. Preferably the surfactants used are saturated.
Preferably the composition comprises between 5 to 70 wt% of surfactants selected from anionic and non-ionic surfactants, most preferably 15 to 55 wt %. The fraction of non-ionic surfactant is preferably from 0.05 to 0.50 of the total wt% of the anionic and non-ionic surfactant, preferably from 0.1 to 0.4, more preferably from 0.2 to 0.3.

Non-ionic

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. Preferred nonionic detergent compounds are C₆ to C₂₂ alkyl phenol-ethylene oxide condensates, generally 5 to 9 EO, i.e. 5 to 9 units of ethylene oxide per molecule, and the condensation products of aliphatic C₈ to C₁₈ primary or secondary linear or branched alcohols with ethylene oxide, with 5 to 9 EO.
The non-ionic surfactant preferably contains an alkyl alkoxylate. The alkyl alkoxylate is preferably and alkyl ethoxylate, with formula R¹(OCH₂CH₂)_pOH: where R¹ is an alkyl group that may be primary or secondary and contains C10-C16 carbon atoms. Most preferably R¹ is a C12-C15 primary alkyl chain. p is from 5 to 9, preferably from 7 to 9.
The preferred alkyl alkoxylate is preferably greater than 50% of all the non-ionic present, more preferably greater than 70%, most preferably greater than 90%.

1) Anionic Surfactants

Suitable anionic detergent compounds which may be used are usually watersoluble 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 C₈ to C₁₈ alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl C₉ to C₂₀ benzene sulphonates, particularly sodium linear secondary alkyl C₁₀ to C₁₅ benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from palm kernel, tallow or coconut oil, methyl ester sulfonates, and synthetic alcohols derived from petroleum. Most preferred anionic surfactants are sodium lauryl ether sulfate (SLES), particularly preferred with 1 to 3 ethoxy groups, sodium C₁₀ to C₁₅ alkyl benzene sulphonates and sodium C₁₂ to C₁₈ alkyl sulphates. The chains of the surfactants may be branched or linear.
Soaps may be present. The fatty acid soap used preferably contains from about 16 to about 22 carbon atoms, preferably in a straight chain configuration. Preferably soap is present at less than 2wt%, more preferably less than 1wt%, most preferably less than 0.5wt% of the formulation.
Preferably, at least 50 wt % of the anionic surfactant are selected from: sodium C₁₁ to C₁₅ alkyl benzene sulphonates; and, sodium C₁₂ to C₁₈ alkyl sulphates.
Even more preferably, the anionic surfactant is sodium C₁₁ to C₁₅ alkyl benzene sulphonates.

Other Ingredients

Other Ingredients may be present. Preferred ingredients are enzymes, dispersants, preservatives, chelating agents, fluorescent brightners, polymers and perfumes. Preferably the perfume is present in a concentration from 0.01 to 5 wt %, most preferably 0.5 to 1.5 wt %.
Hydrogen peroxide bleach is preferably absent from the formulation.
Preferably enzymes are proteases, amylases, lipases, endoglucanases, and pectate lyases.
Other dyes may be present in the laundry liquid composition to modified the colour, these are preferably present at levels of less than 0.005wt%. preferred chromophores are azo, anthraquinone and triphenylmethane. Dyes present to modify the colour are preferably sulfonated.
Preferred polymers are acrylic acid/maleic acid copolymers, alkoxylated poly(ethleneimine) polymer and polyvinyl acetate grafters polyethylene oxide copolymer having a polyethylene oxide backbone and multiple polyvinylacetate side chains.
The pH of the laundry liquid composition may be modified with standard acids and bases. Preferred ingredients for modifying the pH are monoethanolamine, diethanolamine, triethanolamine, hydrochloric acid, caustic soda, citric acid, sulphuric acid. Most preferably monoethanolamine or triethanolamine is added to acidic anionic surfactants till the required pH is obtained.
To avoid photodegradation of the formulation it is preferred if the laundry liquid composition is stored in non-transparent packs. The wall of a non-transparent pack reduces the visible light intensity measured at 600nm, passing through it, by at least 60%, preferably 90%, most preferably 95%.
The composition preferably comprises a fluorescent brightener (optical brightener). Fluorescent brighteners are well known and many such fluorescent brightners 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 the composition is generally from 0.005 to 2 wt %, more preferably 0.01 to 0.1 wt %. Preferred classes of fluorescer are: Di-styryl biphenyl compounds, e.g. Tinopal (Trade Mark) CBS-X, Di-amine stilbene di-sulphonic acid compounds, e.g. Tinopal DMS pure Xtra and Blankophor (Trade Mark) HRH, and Pyrazoline compounds, e.g. Blankophor SN. 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}stilbene-2-2' disulfonate, disodium 4,4'-bis{[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)]amino} stilbene-2-2' disulfonate, and disodium 4,4'-bis(2-sulfostyryl)biphenyl.

Experimental

The dye Violet AP13 was synthesis following literature procedures and analysed by HPLC. It was shown to be a mix of azo thiophene dye covalently linked to one or two polymer chain(s), wherein the polymer chain contains an ester group with a carboxylic acid group on the β carbon to the ester group. The structures are:
and
Violet AP13 was dissolved in demineralised water with the pH set to 6.5, 7.0(reference) and 10.0(reference). The solutions were heated to 80°C and aliquots removed over time and the level of Violet AP13 measured by calibrated HPLC. The pH was measured over time and did not vary.
The decrease in concentration of Violet AP13 was linear with time till greater than 60% of the dye had been lost. A linear regression was made and the time taken, t _1/2 for 50% of the Violet AP13 to be lost measured. The results are summarised in the table below:

pH t _1/ ₂ in hours

6.0(reference) insoluble

6.5 266

7.0 (reference) 175

10 (reference) 5
The decomposition of Violet AP13 takes a longer time at pH 6.5, than pH 7.0 or 10.
At a pH of 6.0 and below the dye becomes insoluble in water.

Example laundry liquid composition

Ingredient Wt%	A	B	C
Dodecylbenzenesulfonate	20	15	15
Propylene glycol	10	8	12
C12-C14 alcohol ethoxylate with an average of 7 ethoxylates	19	20	15
Laureth sulphate	9	12	8
Palm kernelate	0	0.5	0
Polyethyleneimine ethoxylate (PEI 600 with 20 ethoxylates -per NH)	8	5	8
1,2, propanediol	5	4	6
Enzymes	1	2	2
perfume	1	1.5	1.5
Monoethanol amine and water	Remainder to pH=6.5	Remainder to pH=6.4	0
triethanol amine and water	0	0	Remainder to pH=6.5

The laundry liquid composition may be tested as follows.
The dilution pH is measured by adding 10 g of the laundry liquid composition into 40 g of demineralised water and the pH measured at 293 K; the demineralised water has a pH of 7.0 (pH neutral) before addition of the laundry liquid composition. The demineralised water is also purged with nitrogen before the addition of the laundry liquid composition and pH measured within five minutes of dissolution of the laundry liquid composition in the demineralised water; dissolution is facilitated by stirring.
Preferably the pH of the laundry liquid composition is that same as that of the dilution pH. The pH is measured using a calibrated pH probe.

Claims

A laundry liquid composition comprising:
from 0.0001 to 1wt% of a dye, the dye covalently linked to a polymer chain(s), wherein the polymer chain contains an ester group with a carboxylic acid group on the β carbon to the ester group and the laundry liquid composition comprises from 1 to 80wt% water and the laundry liquid composition having a dilution pH in the range from 6.1 to 6.9, wherein the dilution pH is measured by adding 10 g of the laundry liquid composition into 40 g of pH neutral demineralised water and the pH measured at 293 K.
A laundry liquid composition according to claim 1, wherein the dilution pH of the laundry liquid composition is in the range from 6.2 to 6.7.
A laundry liquid composition according to claim 2, wherein the dilution pH of the laundry liquid composition is in the range from 6.4 to 6.6.
A laundry composition according to any one of the preceding claims, wherein the polymer chain(s) is/are polyoxyalkylene chain(s) having from 2 to 10 repeating units.
A laundry composition according to claim 4, wherein the polyoxyalkylene chain(s) having from 2 to 10 repeating units is/are polyoxyethylene chain(s).
A laundry liquid composition according claim 5, wherein the dye is of the form selected from:
wherein R₁ and R₂ are independently selected from H, C1-C20 alkyl and C3-C20 alkylene and integer n takes values from 1 to 9 and integer m takes values from 0 to 9.
A laundry liquid composition according to claim 6, wherein R₁ and/or R₂ is/are C3-C20 alkylene, wherein the alkylene contains one carbon-carbon trans double bond starting 3 carbons removed from the carboxylic acid.
A laundry liquid composition according to any preceding claim, wherein the dye is an azo thiophene dye.
A laundry liquid composition according to claim 8, wherein the azo thiophene dye is a mono-azo thiophene dye.
A laundry liquid composition according to claim 9, wherein the dye selected from:
and,
wherein integer n takes values from 1 to 9 and integer m takes values from 0 to 9.
A laundry composition according to any one of the preceding claims, wherein the composition comprises from 2 to 70 wt% of a surfactant.
A laundry composition according to any one of the preceding claims, wherein the surfactant comprises from 50 to 100 wt % anionic surfactant.