WO2002036723A1

WO2002036723A1 - Bleaching composition comprising radical initiators

Info

Publication number: WO2002036723A1
Application number: PCT/EP2001/012579
Authority: WO
Inventors: Stephen Norman Batchelor; Lynnette Fairclough; Jacqueline Williams
Original assignee: Unilever Plc; Unilever Nv; Hindustan Lever Limited
Priority date: 2000-11-02
Filing date: 2001-10-29
Publication date: 2002-05-10
Also published as: AU2002220674A1; AR031189A1; GB0026831D0

Abstract

The invention relates to bleaching compositions comprising radical initiators. More particularly the invention relates to laundry treatment compositions for the spot treatment of soiled articles and to a process using the said compositions. The invention provides a fabric treatment composition which comprises: a) a radical initiator, and b) a solvent which does not swell the amorphous regions of cotton. It is believed that the use of a solvent which is non-swelling prevents the passage of the initiator into the regions of the fibres where the dye resides while allowing the initiator to come into contact with the stain, which is essentially superficial. Preferred solvents are those with logP values greater than 1, most preferably greater than 2. The present invention further provides a method for the treatment of fabrics which comprises applying to the fabric a composition according to the invention.

Description

BLEACHING COMPOSITION COMPRISING RADICAL INITIATORS

Technical Field

The present invention relates to bleaching compositions comprising radical initiators. More particularly the invention relates to laundry treatment compositions for spot treatment of soiled articles and to a process using the said compositions.

Background of the Invention

Radical photo-initiators have recently become known as stain bleaches for laundry applications. These are materials which on exposure to light generate reactive radicals which cause chemical changes in the stain and decolourise it. Radical photo-initiators are well known in the unrelated fields of polymerisation and curing reactions. ,

Other types of radical initiators are known (such as thermal or chemical initiators) and use of these in bleaching and sewage or other effluent treatment has also been envisaged. For convenience, the term ^,radical-initiator' as used in this patent, will include both photo-initiators and thermal- initiators, but exclude chemical radical initiators.

It is a well established problem in the field of laundry bleaching that compounds which can bleach stains will also have the capacity to bleach dyes which may be intentionally present in the cloth. Consequently, much effort has been spent in finding bleaches which are effective against stains but are ineffective against dyes. This problem is especially difficult to solve porous fibres such as dyed cotton and other dyed cellulosics.

UK Patent application no: 9917451.8, teaches that photo- initiators with high logP, (logarithm of octanόl-water partition coefficient) , values give good stain bleaching with little dye damage on the fabric. This is highly desirous as consumers wish to remove stains without damaging their coloured fabric. The most preferred photoinitiators are those with logP values in excess of 4.0.

Many effective photoinitiators have logP values much lower than 4.0 and are known to give some fabric dye damage particularly when used at high levels.

For example 1-hydroxy-cylcohexyl-phenyl-ketone has logP = 2.81, 2-hydroxy-4' -hydroxyethoxy-2-methylpropiophenone has logP ^■= 0.84.

It would be advantageous if these and other low logP initiators could be used without causing damage. _

- A prior ^'approach ^"to ^"this^' problem is disclosed in co-pending UK patent application UK 9929693.1. This teaches the use of radical terminators in conjunction with radical initiators to reduce dye damage. However the use of two active ingredients may not always be desirable, particularly for reasons of cost. Brief Description of the Invention

We have found that application of radical initiators from solvents which do not swell the amorphous regions of cotton, leads to much less damage but still give good stain bleaching.

The swelling behaviour of cotton is discussed in ^ΛCellulose -Structure Accessibility and Reactivity' , Gordon and Breach Science Publishers and references therein. Commonplace solvents such as water and ethanol are effective at swelling the amorphous regions of cotton and other cellulosics.

Accordingly, the present invention provides a fabric treatment composition which comprises:

a) a radical initiator, and

b) a solvent which does not swell the amorphous regions of cotton.

It is believed that the use of a solvent which is non- swelling prevents the passage of the initiator into the regions of the fibres where the dye resides while allowing the initiator to come into contact with the stain, which is essentially superficial. Preferred solvents are those with logP values greater than 1, most preferably greater than 2.

Preferred solvent evaporates at room temperature (20 degrees Celcius) or may easily be removed by physical wiping so that oily solvent marks on the fabric are prevented.

The present invention further provides a method for the treatment of fabrics which comprises applying to the fabric a composition according to the invention.

Detailed Description of the Invention

The preferred radical initiators are photo and thermal initiators. The use of photo initiator systems is preferred as sunlight and other suitable sources of illumination are generally freely available. It is commonplace, for example, to dry laundered articles in sunlight.

Types of initiator:

The photo-initiators can be hydrogen abstraction radical photo-initiators. These include benzophenones, acetophenones, pyrazines, quinones and benzils.

Bond cleavage photo-initiators are preferred. Suitable bond cleavage radical initiators may be selected from the following groups: (a) alpha amino ketones, particularly those containing a benzoyl moiety, otherwise called alpha-amino acetophenones, for example 2-methyl 1- [4-phenyl] -2- morpholinopropan-1-one (Irgacure 907, trade mark, ex CIBA) , (2-benzyl-2-dimethyl amino-l-(4- morpholinophenyl) -butan-1-one (Irgacure 369, trade mark, ex CIBA) ;

(b) alphahydroxy ketones, particularly alpha-hydroxy acetophenones, eg (1- [4- (2-hydroxyethoxy) -phenyl] -2- hydroxy-2-methyl-l-propan-l-one) (Irgacure 2959, trade mark, ex CIBA) , 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, trade mark, ex CIBA); 2-hydroxy-2-methyl- 1-phenylpropan-l-one (Esacure ™ KL200 ex Lamberti SPA) ; and, oligomeric polyfunctional alpha-hydroxyketones (such as Esacure KIP150 ex Lamberti SPA) ;

(c) phosphorus-containing photoinitiators, including monoacyl and bisacyl phosphine oxide and sulphides, for example 2-4-6- (trimethylbenzoyl) diphenyl-phosphine oxide, bis (2, 4, 6-trimethylbenzoyl) -phenyl-phosphine oxide (Irgacure 819, trade mark ex CIBA), (2,4,6- trimethylbenzoyl) phenyl phosphinic acid ethyl ester (Lucerin TPO-L (trade mark) ex BASF) ;

(d) dialkoxy acetophenones; particularly Benzildimethylketal (Esacure ™ KBl ex Lamberti SPA) ;

(e) alpha-haloacetophenones;

(f) trisacyl phosphine oxides; and, (g) bezoin and bezoin-based photoinitiators.

Further suitable radical photoinitiators are disclosed in WO 9607662 (trisacyl phosphine oxides), US 5399782

(phosphine sulphides), US 5410060, EP-A-57474, EP-A-73413 (phosphine oxides), EP-A-088050, EP-A-0117233, EP-A-0138754, EP-A-0446175 and US 4559371.

Other suitable radical photoinitiators are disclosed in

EP-A-0003002 in the name of Ciba Geigy, EP-A-0446175 in the name of Ciba Geigy, GB 2259704 in the name of Ciba Geigy (alkyl bisacyl phosphine oxides) , US 4792632 (bisacyl phosphine oxides) , US 5554663 in the name of Ciba Geigy (alpha amino acetophenones) , US 5767169 (alkoxy phenyl substituted bisacyl phosphine oxides) and US 4719297 (acylphosphine compounds).

Radical photoinitiators are discussed in general in A.F. Cunningham, V. Desorby, K. Dietliker, R. Husler and D.G.

Leppard, Chemia 48 (1994) 423-426 and H.F.Gruber, Prog. Polym. Sci., 17, (1992), 953-1044.

The preferred radical photoinitiators become active when excited by radiation falling generally in the range 290-800 nm. For example, natural sunlight, which comprises light in this region, will be suitable for causing the radical photoinitiator to undergo one of the reactions described above . Preferably, the radical photoinitiator has a maximum extinction coefficient in the ultraviolet range (290-400 nm) which is greater than 100 mol^~1lcm^'"1. Suitably, the radical photoinitiator is a solid or a liquid at room temperature.

Particularly preferred photo-initiators include alpha hydroxy ketones .

Suitably, the radical photoinitiator is substantially colourless and gives non-coloured photo products upon undergoing one of the reactions set out above.

Optionally, the compositions comprise sensitisers such as thioxanthones, for example as described in EP-A-0088050, EP-A-0138754.

The radical photoinitiators are preferably activated by ambient light eg, domestic lighting or sunlight. However, a separate light source (for example a tungsten filament or gas discharge tube) may be employed for activation of the photoinitiator .

In the alternative, the substance which is used in the present invention may be a thermal initiator which decomposes to form radicals on heating. As will be apparent, there will be some degree of overlap between the different classes of substances which may be used in these two aspects of the invention. Some radical photoinitiators also decompose by heating (particularly at higher temperatures) and some thermal initiators decompose on exposure to light (particularly at shorter wavelengths) . Suitable substances which decompose on heating include compounds comprising an azo group or a peroxygen group. Preferred materials exclude those containing a peroxygen group and include those which form a carbon-centred radical rather than an oxygen centred radical.

The thermal initiators are preferably stable at ambient temperature. Temperatures to which the thermal initiators should be heated to cause them to decompose are preferably in the range of up to 100°C, more preferably from 35°C to 90°C, most preferably 35°C to 40°C. Heat may conveniently be applied by means available in the laundering environment such as by use of an iron or tumble drier.

Mode of application:

The initiator may be applied to the fabric from the solvent, the solvent removed by evaporation then irradiated, or the fabric irradiated wet, or the fabric irradiated in a solution of the initiator.

The solvent may be contained in a wipe and the wipe used to physically remove stain and apply photoinitiator to it.

The non-swelling solvent and/or initiator may be a perfume material or the carrier of a perfume material. Inclusion of the initiator in a final composition together with the perfume is advantageous as both classes of materials may require careful dosing and the composition is generally not subjected to heating once the perfume has been added. Conveniently, the solvent is miscible with water, thereby allowing it to be easily removed from the fabric.

The non-swelling solvent containing the initiator may be made part of an emulsion or a microemulsion . e.g. oil in water, oil in ethanol. Surprisingly, we have found that when the phase of the emulsion that does not contain the initiator is a solvent such as water or ethanol, which would otherwise swell the amorphous regions of cotton, a benefit is still obtained.

Emulsions and microemulsion are well known in the art see e.g. ^Surfactant Science Series' (Marcel Dekker Inc., particularly vol 6,24,30,61); ^Modern Aspects of Emulsion Science' (Royal Society of Chemistry ISBN 0-85404-439-6) and references therein.

The emulsion may contain a water-soluble or alcohol-soluble radical terminator to further reduce damage.

Preferred solvents are selected from ketones, alkanes, aromatics, esters, and alcohols. Of these, 2-hexanone, toluene, hexane, heptane, ethyl propionate, n-butyl acetate and n-pentanol are particularly preferred

The photoinitiator system must ^"generally ^' be stored in the absence of light of wavelength below 500nm, to avoid photo- reaction. An opaque packaging is sufficient for this purpose. The invention will be further described with reference to the following non-limiting examples.

Examples

Example 1

Cotton cloth was reactively dyed with Remazol Black B so that the cloth contained 1.5xl0^~4 mol kg^-1 of dye. This cloth is a sensitive monitor of dye damage.

The cloth was dipped in acetone containing 0.2% by weight of 2-hydroxy-4' -hydroxyethoxy-2-methylpropiophenone (Irgacure 2959, ex Ciba Speciality Chemicals) , the acetone evaporated and then the cloth irradiated in Weatherometer for 18 minutes. The CIELAB ΔE values of the cloths compared to the original untreated fabric was then measured using a reflectance spectrometer.

The experiment was repeated for a wide variety of solvents other than acetone and also with the initiator 1-hydroxy- cylcohexyl-phenyl-ketone (Irgacure 184, ex Ciba Speciality Chemicals) .

The results are displayed in table 1, alongside the logP of the solvent which was taken from literature or calculated using standard methods (J.Sangster J. Phys . Ref . Data 18, 1111, 1989; A.J.Leo Chem.Rev. 93, 1281, 1993 and refs. therein). Solvents with a logP greater than 1 and the corresponding results are indicated in bold type.

For both initiators as the logP of the solvent becomes larger the ΔE values drops, reflecting a reduction in dye damage. Least damage is seen when logP > 2.

Table 1

Table 1 - damage caused to Remazol Black B cloth by photoinitiator applied from different solvents. Untreated cloth (irradiation only) ΔE = 0.34 Example 2

The experiment of example 1 was repeated using white cloth heavily stained with β-carotene (Equest, Newcastle GB) and the ΔE values measured to white originals. Control experiments using the solvents alone and irradiation were also performed.

Application of the initiator from all solvents showed great bleaching of the stain than from the solvent alone.

The results are displayed in Table 2 and Table 3

Table 2

Table 2 Bleaching of β-carotene stained cotton clothes by radical initiators applied from different solvent systems, Values displayed are the CIELAB ΔE values relative to unstained cloth before and after treatment.

Table 3

Table 3 Bleaching of β-carotene stained cotton cloth by solvents and light alone. Values displayed are the CIELAB ΔE values relative to unstained cloth before and after treatment. In many cases the stain was darkened by this treatment . Example 3

Irgacure 184 was dissolved in the solvent DF2000 (a synthetic aliphatic hydrocarbon, logP>3, ex. Exxon Chemical Company, CAS 64742-48-9) in a glass vessel, into this was placed cotton stained with β-carotene and the Remazol Black cloth described in example 1.

The glass vessel was then irradiated in the WOM, such that the cloth was in the light. There was approximately 1 cm from the front wall of the vessel to the cloth. After 6 minutes the cloth was removed, the solvent evaporated and the stain bleaching and dye damage was then measured.

The experiments were repeated with various amount of

Irgacure 184 dissolved in the solvent and then with the solvents, decamethyltetrasiloxane (Dow Corning, logP>l, CAS 141-62-8) and a 1:1 mixture HFE7100: decamethyltetrasiloxane. (HFE7100 is a mixture of methyl nonafluoroisobutyl ether and methyl nonafluorobutyl ether, logP>2, ex. The 3M company) .

The results are shown in Table 4.

In all cases stain bleaching was observed with little dye damage. Values are much smaller then when cloth containing Irgacure 184 is irradiated wet with water, e.g. with 0.2% Irgacure 184 applied from ethanol then wetted with water ΔE=10 . Table 4

Table 4 Stain bleaching and dye damage observed with

Irgacure 184 in solutions of solvents. The ΔE value of the stain prior to treatment was 65.

Example 4

0.5% by weight of Irgacure 184 was dissolved in hexane. 50ml of water containing 2.5% by weight of surfactant (coco20, ) was added to 7.5ml of the hexane solution and the mixture sonified to produce an oil in water emulsion. The emulsion was dripped onto cotton stained with β-carotene and the Remazol Black cloth (both described in example 1) . This delivered 0.06% weight of the initiator to the cloth. The cotton was dried in air for several hours then placed in a WOM for 6 minutes and the stain bleaching and dye damage measured by a reflectance spetrometer.

The experiment was repeated using heptane, octane, nonane and dodecane, and compared to control experiments using equivalent emulsion that did not contain Irgacure 184. The results are displayed in Table 5. Good stain bleaching and little dye damage is observed, however the stain bleaching is reduced by the long chain alkane, dodecane.

When 0.06% Irgacure 184 was applied to the dyed cloth from ethanol, dried and irradiated for 6 minutes, a dye damage of ΔE=1.15 was observed. Dye damage is larger compared to the emulsions .

Table 5

Table 5 Stain bleaching and dye damage observed with

Irgacure 184 deposited from emulsion systems and irradiated after drying. The ΔE value of the stain prior to treatment was 65, the ΔΔE is the reduction in this value after treatment, so that negative values indicate a darkening of the stain. (ΔΔE = ΔE (before) -ΔE (after)).

Example 5

The experiments of example 4 were repeated but the irradiation done immediately after the emulsions applied, i.e. the cloths were wet and not dried. The results are displayed in Table 6.

When 0.06% Irgacure 184 was applied to the dyed cloth from ethanol, dried, wet with water then irradiated for 6 minutes, a dye damage of ΔE=2.86 was observed. Dye damage is much larger compared to the emulsions. '

Table 6

Table 6 Stain bleaching and dye damage observed with Irgacure 184 deposited from emulsion systems and irradiated without drying. The ΔE value of the stain prior to treatment was 65, the ΔΔE is the reduction in this value after treatment, so that negative values indicate a darkening of the stain. (ΔΔE = ΔE (before) -ΔE (after)).

Example 7

The experiments of example 1 where repeated using the alcoholic solvents and blue, red and green cotton cloth containing 9.3^χl0^~5 mol kg^-1 cotton of Remazol Brilliant Blue R, 8.3^χl0^"5 mol kg^-1 cotton of Procion Red HE-7B and 4.4^χl0^"4 mol kg^-1 cotton of Direct Green 26. The results are displayed in Table 7. Once again deposition from solvent with high logP (n-Pentanol) gives much less dye damage (lower ΔE values) .

Table 7

Table 7 Damage caused to various dyed cotton cloths by photoinitiators applied from different alcohols and expressed in CIELAB ΔE values relative to the original cloth. Cloths dipped in pure solvent then irradiated gave ΔE values of 1.2, 1.0, 2.2. 0.5, 0.1 for the blue cloth with methanol, ethanol, n-propanol, n-butanol and n-pentanol respectively. Similarly 0.9, 1.3, 0.2, 0.6, 0.5 for the red and 1.8, 1.5, 2.1, 1.9, 1.5 for the green cloth.

Example 8

The experiments of example 1 were repeated using 0.2% Esacure KIP 150 (ex Lamberti Spa), 0.2% Esacure KTO/46 (ex Lamberti Spa), 0.2% Esacure KIP 100F, and 0.2% Lucirin TPO-L (ex BASF), and ethanol and toluene solvents. The dyes damage observed is given in the table 8.

Table 8

Table 8 dye damage observe on Remazol Black B cloth when various initiator are applied from a swelling and non- swelling solvent.

In ^"all cases dye^" damage was ^'much smaller i the non-swelling solvent toluene.

When the experiments were repeated using white cotton cloth stained with β-carotene (as per example 2), good bleaching of the stain above control, was observed when the initiators were deposited with both solvents (ethanol and toluene) .

Claims

1. A fabric treatment composition, which comprises:

a) a radical initiator, and

b) a solvent which does not swell the amorphous regions of cotton.

2. A composition according to claim 1, wherein the solvent has a logP value greater than 1.

3. A composition according to claim 2, wherein the solvent has a logP value greater than 2.

4. A composition according to claim 1, wherein the solvent is selected from ketones, alkanes, aromatics, esters, alcohols and mixtures thereof.

5. A composition according to claim 4, wherein the solvent is selected from 2-hexanone, toluene, hexane, heptane, ethyl propionate, n-butyl acetate, n-pentanol and mixtures thereof.

6. A composition according to any preceding claim, wherein the solvent is miscible with water.

7. A composition according to any preceding claim, wherein the solvent is volatile at 20 degrees Celcius.

8. A composition according to any preceding claim, where the radical initiator is a photo or thermal initiator.

9. A composition according to any preceding claim, wherein the initiator is a bond cleavage photoinitiator.

10. A composition according to claim 7, wherein the initiator is selected from:

(a alpha amino ketones,

(b alphahydroxy ketones,

(c phosphorus-containing photoinitiators,

(d dialkoxy acetophenones;

(e alpha-haloacetophenones ;

trisacyl phosphine oxides;

(g bezoin and bezoin-based photoinitiators, and,

(h mixtures thereof.

11. A composition according to claim 7, wherein the radical photoinitiator becomes active when excited by radiation falling generally in the range 290-800 nm.

12. A composition according to claim 7, wherein the radical photoinitiator has a maximum extinction coefficient in the ultraviolet range (290-400 n ) which is greater than 100 mol^-1lcm^_1.

13. A composition according to any preceding claim, in combination with a wipe or swab.

14. A composition according to any preceding claim, further comprising one or more perfume components.

15. A composition according to any preceding claim, in the form of an emulsion.

16. A composition according to any preceding claim, further comprising a radical terminator.

17. A method for the treatment of fabrics which comprises applying to the fabric a composition according to any of claims 1-16.