GB2129458A - Washing composition - Google Patents

Abstract

A washing composition comprising an alkali metal perborate; an activator for decomposing the perborate, selected from cyanamide and metal salts thereof; and a proteolytic enzyme obtained from a strain of Bacillus. The washing compositions according to this invention lead simultaneously to activation of the alkali metal perborate and to laundering of protein stains and consequently make it possible to carry out low temperature washes whilst removing protein stains.

Description

SPECIFICATION Washing composition This invention relates to a washing composition for laundering at low temperatures and for removing protein stains. More precisely, the invention relates to a washing composition for laundering at a temperature equal to or below 60"C and for removing protein stains, i.e. marks such as blood, egg, Indian ink stains and the like.

Hitherto, it has only been possible to solve these two problems separately.

Activators are known which enable peroxide-based cleaning agents to act at a temperature below 600 C, by destablising them. The activators used industrially or most often mentioned are products which react with the peroxides to produce peracetic acid which is a powerful low-temperature cleaning agent. These activators include tetra-acetylethylenediamine (TAED), tetraacetylglycoluryi (TAGU), aacetoxy-a-methyl-N,N'-diacetylmalonamide (AP 31) as described in our French Patents 2,363,541 and 2,363,629, and cyanamide and its derivatives as described in French Patent 2,340,371.

In order to remove protein stains, enzymatic products have to be used.

In the past, the activation of peroxides and the removal of protein stains have not been implemented simultaneously owing to the incompatibility between the enzymatic activity and the presence of peracetic acid in the washing composition.

The present invention aims to overcome this difficulty, and provides a washing composition based on perborate, which enables these two objectives to be met, by effecting a double selection in the choice of the activator and in the choice of the enzyme.

The washing composition based on alkali metal perborate according to the invention comprises a decomposition activator for the perborate, selected from cyanamide and the metal salts thereof, such as calcium sodium and magnesium salts, and a proteolytic enzyme obtained from a strain of Bacillus.

The quantities of activator and enzyme are from 2 to 8% by weight of the total washing agent for the activator, and from 0.4 to 0.8% by weight of the total washing agent for the enzyme.

An unexpected synergistic effect is obtained with compositions in accordance with the invention, as is demonstrated by the following tests. These tests show that the combination of an enzyme and an activator other than as provided according to the invention does not permit simultaneous removal of protein stains and laundering at 600C.

The invention will be described in more detail with reference to the following Examples.

EXAMPLES The Examples were carried out using an AHIBA apparatus which permits both agitation of the washing bath and regulation of the temperature.

Four standardised EMPA cotton fabrics were used, bearing particular stains: wine, cocoa, tea, whilst the EMPA 11 6 fabric was stained with milk, blood and Indian ink. The stain removal was measured optically using an ELREPHO photometer made by Zeiss.

The basic washing powder used is standardised EMPA washing powder This contains no perborate and no blue additives. Its composition is typical of the washing products currently on the market.

The percentages by weight of the various constituents relative to the basic washing powder are as follows: sodium perborate : 15%, i.e. 1 g/l of bath - activator : 2.94% - proteolytic enzyme obtained from a strain of Bacillus : 0.4%, i.e. 0.0268 g/l of bath.

EMPA washing powder is added to make up 6.7 g/l of bath.

During each test process, the temperature was raised to 600C in 30 minutes and kept at this level for 30 minutes.

After the wash, the cleaning powder of the bath used is determined for each fabric, defined as follows: final whiteness -- initial whiteness cleaning power = x 100 100 - initial whiteness EXAMPLES 1 to 8 The results of these Examples are given in Table I below.

TABLE I

Fabric EMPA 116 Example Composition of bath Wine Cocoa Tea (protein No. EMPA EMPA stain) 1 basic wash agent EMPA Perborate 15 % 41,5% 8,1% 23,6% 0,73% 2 basic wash agent EMPA Perborate 15 % 40,3% 17% 23,3% 22,7% Enzyme 0,4% 3 basic wash agent EMPA Perborate 15 % 44,6% 9,6% 30,4% 0,62% AP 31. 2,94 % 4 basic wash agent EMPA Perborate 15 % 44,6% 18,1% 31,2% 17,8% AP 31. 2,94 % Enzyme 0,4 % 5 basic wash agent EMPA Perborate 15 % 48,7% 5% 29,1% 0,5% TAED 2,94 % 6 basic wash agent EMPA Perborate 15 % 47,7% 16% 29% 15,2% TAED 2,94 % Enzyme 0,4 % 7 basic wash agent EMPA Perborate 15 % 51,8% 11% 28,8% 0,8% Cyanamide 2,94 % 8 basic wash agent EMPA Perborate 15 % 51,3% 21,3% 33,4% 33,1% Cyanamide 2,94 % Enzyme 0.4 % The laundering power of the bath used is given for fabrics bearing EMPA wine stains, EMPA cocoa stains, tea stains and for an EMPA 11 6 fabric with protein stains (milk, blood and Indian ink stains).

The above tests give rise to the following comments: EXAMPLE 1 This Example relates to the performance of a commercial-type washing agent at 60 C.

EXAMPLE 2 The addition of an enzyme has no effect on the laundering of fabrics stained with wine and tea but significantly improves the results on the EMPA 11 6 fabric with its protein stains and the cleaning of the fabric stained with cocoa.

EXAMPLES 3 and 5 The use of an activator for the perborate of the TAED or AP 31 type yields an improvement in fabrics stained with wine or tea. The effects are negligible for the other stains.

EXAMPLES 4 AND 6 These Examples relate to the joint use of an activator (AP 31, TAED) and of an enzyme identical to that in Example 2.

On the EMPA 11 6 fabric with protein stains, the laundering effect is inferior to that obtained in Example 2.

However, for the fabrics stained with cocoa, the results of Examples 4, 6 and 2 are equivalent.

EXAMPLE 7 The results are equivalent to those of Examples 3 and 5 for fabrics stained with tea or for the EMPA 11 6 fabrics.

EXAMPLE 8 This Example illustrates an embodiment of the invention. On each of the four fabrics tested, the cleaning power obtained is better than for the bath compositions of the other Examples. This Example shows that there is excellent compatibility between the enzyme and the free cyanamide. Moreover, a synergistic effect is observed. The action of the enzyme on the EMPA 116 fabric with its protein stains is better than that observed in Example 2 (enzyme on its own).

Claims (4)

1. A washing composition comprising an alkali metal perborate; an activator for decomposing the perborate, selected from cyanamide and metal salts thereof; and a proteolytic enzyme obtained from a strain of Bacillus.

2. A washing composition as claimed in Claim 1, wherein the activator is selected from calcium, sodium and magnesium salts of cyanamide.

3. A washing composition as claimed in Claim 1 or 2, wherein the quantities of the activator is from 2 to 8% by weight of the total washing composition and the quantity of the enzyme is from 0.4 to 0.8% by weight of the total washing composition.

4. A washing composition as claimed in Claim 1 substantially as described in the foregoing Example 8.