Bleaching detergent compositions

Details Bleaching detergent compositions Bleaching detergent compositions

2000-06-20

2002-04-30

Douyon, Lorna M. (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

Enzyme component of specific activity or source

C510S392000, C510S305000, C510S306000, C510S311000, C510S320000, C510S393000, C510S374000, C510S375000, C510S530000, C008S137000, C008S401000

Reexamination Certificate

active

06380146

ABSTRACT:

TECHNICAL FIELD
The present invention generally relates to bleaching detergent compositions. More in particular, the invention is concerned with the activation of phenol oxidizing enzymes in a process for bleaching stains on fabrics during washing, without provoking dye damage.
BACKGROUND AND PRIOR ART
Bleaching detergent compositions are well known in the art for removing stains on garments. Modern detergent compositions employ peroxygen compounds such as sodium perborate or sodium percarbonate to oxidize the stains, usually in combination with bleach catalysts such as TAED.
Redox enzymes have also been suggested to bleach stains on fabrics. Redox enzymes are enzymes which catalyze the transfer of electrons from an electron donor to an electron acceptor. In the case of phenol oxidizing enzymes, the electron donor is usually a phenolic compound and the electron acceptor is molecular oxygen or hydrogen peroxide, which is thereby reduced to H
2
O. Phenol oxidizing enzymes are capable of using a wide variety of different phenolic compounds as electron donors, but they are very specific for molecular oxygen or hydrogen peroxide as the electron acceptor.
Examples of phenol oxidizing enzymes which use molecular oxygen as electron acceptor are laccases (EC 1.10.3.2), bilirubin oxidases (EC 1.3.3.5), mono phenol oxidizing enzymes (EC 1.14.18.1), catechol oxidases (EC 1.10.3.1). Phenol oxidizing enzymes that use hydrogen peroxide as electron acceptor are called peroxidases.
Phenol oxidizing enzymes can be utilised for a wide variety of applications, including the detergent industry, the paper and pulp industry (U.S. Pat. No. 4,690,895), the textile industry and the food industry. In the detergent industry, phenol-oxidizing enzymes have been used for preventing the transfer of dyes in solution from one textile to another during detergent washing, an application commonly referred to as dye transfer inhibition.
For example, the use of peroxidases for bleaching fabrics during washing has been suggested in EP-A-424 398 (Novo Nordisk). WO-A-91/05839 (Novo Nordisk) describes the inhibition of dye transfer during the wash by means of peroxidase or an enzyme exhibiting oxidase activity on phenolic compounds. The compositions are said to bleach any dissolved textile dye so that no dye can redeposit upon the fabric.
It is also known that the activity of phenol oxidizing enzymes may be increased by the addition of certain organic compounds. The use of such activated enzyme systems for various purposes has also been described, for instance for inhibiting dye transfer in a washing process. The above mentioned WO-A-91/05839 (Novo Nordisk) describes that the addition of another oxidisable substrate may enhance the enzyme activity. Examples of such oxidisable substrates or “enhancers” are certain phenolic compounds, e.g. 2,4-dichlorophenol.
In three subsequent patent applications (WO-A-94/12619, WO-A-94/12620 and WO-A-94/12621, all Novo Nordisk) it is disclosed that the action of peroxidase in such anti dye-transfer compositions may be enhanced by the addition of a number of aromatic compounds, of which 2,2′-azo-bis-(3-ethylbenzo-thiazoline-6-sulphonate (ABTS) and Phenothiazine-10-propionate (PTP) appear to be preferred compounds.
The inventors of the present invention have identified an unexpected problem which may occur when phenol oxidising enzymes are used in combination with enhancers compounds to clean soiled fabrics. It was found that enhancers which effectively boost the bleach activity of phenol oxidizing enzyme on stains, may under certain circumstances result in the deterioration of visual appearance of garments. Thus, the enzymatic bleaching of the dyes of coloured fabric could result in undesirable dulling of the garment. This enzymatic bleaching-related dye damage has not been previously discovered in laundry applications and no solutions are at present available. A complicating factor in studying this phenomenon is, that the undesirable dulling of the garment may only become apparent after repeated washing.
Therefore, there is a particular need for bleaching detergent compositions comprising a phenol oxidizing enzyme and an enhancer which specifically bleach stains on fabric, without deteriorating the appearance of coloured garments.
Unexpectedly, it was found that the problem cannot be solved by selecting a particular enhancer or a particular phenol oxidizing enzyme. Rather, the problem appeared to be associated with specific combinations of enhancer and phenol oxidizing enzymes.
We have now surprisingly found that it is possible to obtain detergent compositions which effective bleach stains on fabrics without deteriorating the appearance of coloured garments, i.e. without causing dye damage, if the Enhancer Index (as herein defined) is kept at a value of at least 12 and preferably between 15 and 50.
DEFINITION OF THE INVENTION
According to a first aspect of the invention, there is provided a bleaching detergent composition comprising one or more surfactants, a phenol oxidizing enzyme and a compound which acts as enhancer for the phenol oxidizing enzyme, said composition having an Enhancer Index as herein defined of at least 12.
Preferably, the composition comprises, as an enhancer for the activity of the phenol oxidizing enzyme, one or more compounds having the formula:
wherein:
A is an optionally substituted electron-withdrawing group, chosen from the group consisting of nitrile, carboxyl, and esters and salts thereof, amides, aldehydes, ketones, sulfoxides, sulfones, or sulphonates, and
B is an optionally substituted electron-donating group, chosen from the group consisting of the oxide anion, sulfide anion, oxides, amines, imines, hydroxides, sulfides, ethers, carboxylic acids, and halogen substituents, and
R
1
-R
5
may each independently represent hydrogen, hydroxy, halogen, nitroso, formyl, carboxyl, and esters and salts thereof, carbamoyl, sulfo, and esters and salts hereof, sulfamoyl, nitro, amino, phenyl, C
1
-C
20
alkyl, C
1
-C
8
alkoxy, carbonyl-C
1
-C
6
-alkoxy, aryl-C
1
-C
6
-alkyl, and R
2
and R
5
together may form an alkylene group or an alkenylene group.
DESCRIPTION OF THE INVENTION
The bleaching detergent composition of the present invention comprise one or more surfactants, a phenol oxidizing enzyme and a compound which acts as enhancer for the phenol oxidizing enzyme, said composition having an Enhancer Index as herein defined of at least 12. The Enhancer Index is defined for the purpose of this invention as the ratio of the bleach effect on tomato stains to the colored monitor P10 (&Dgr;E
tomato stain
/&Dgr;E
P10 colored monitor
) , and is further illustrated in the Examples. This ratio was found to be a useful property of the composition to determine whether a particular bleaching detergent composition provides selective bleaching, i.e. stain bleaching without colour damage. Preferably, the Enhancer Index is at least 15, and in particular in the range of 15-50.
(a) The Surfactant(s)
The enzymatic bleach compositions according to the invention comprise, as a first constituent, one or more detergent-active compounds (surfactants) which may be chosen from soap and non-soap anionic, cationic, nonionic, amphoteric and zwitterionic detergent-active compounds, and mixtures thereof. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in “Surface-Active Agents and Detergents”, Volumes I and II, by Schwartz, Perry and Berch.
The preferred detergent-active compounds that can be used are soaps and synthetic non-soap anionic and nonionic compounds. Anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C
8
-C
15
; primary and secondary alkylsulphates, particularly C
8
-C
15
primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulpho-succinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.
Nonionic surfacta

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