ES3015710T3 - Process for fabric bleaching, products and uses thereof - Google Patents

Abstract

This disclosure relates to the field of the textile and chemical industries, specifically textile dyeing. This disclosure describes a process for bleaching fabrics using a novel enzyme blend combined with a specifically designed chemical system, which reduces the use of caustic soda and hydrogen peroxide in the conventional oxidative bleaching process, replacing the handling of these chemicals. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Procedure for bleaching textile materials, products and their uses

Technical field

This disclosure relates to the field of chemistry and the textile industry, specifically textile dyeing, and to a process for bleaching textile materials, products and uses thereof.

The present disclosure describes a process for bleaching textile materials that uses a novel enzyme combination combined with a specifically designed chemical system, which reduces the use of caustic soda and hydrogen peroxide in the conventional oxidative bleaching process, replacing the handling of these chemicals.

Background

The textile industry (TI) is one of the world's largest industries, currently valued at nearly USD 1.5 trillion. However, it is also one of the most polluting industries in the world, contributing to a significant environmental impact in terms of resource consumption, effluent pollution, and textile product disposal.

It has long been known that wet processing processes are characterized not only by the large volume of water required, but also by the high temperatures and variety of chemicals used. There is a long sequence of wet processing steps that require inputs of water, chemicals, and energy, generating waste at each stage.

Water is a finite resource that is rapidly becoming scarce and is used at all stages of the process, both to transport the chemicals used during that stage and to wash them before beginning the next stage. The water is filled with chemical additives and then discharged as wastewater, which in turn pollutes the environment. Liquid effluents from IT typically have high chemical oxygen demand (COD) and biochemical oxygen demand (BOD), high conductivity, and color.

Along with direct pollution and water consumption, the processes in this industry are typically carried out at high temperatures, also representing a very high level of energy consumption. Most of the energy used in IT is still derived from coal and fossil fuels, meaning this energy use is a significant source of greenhouse gas emissions.

Minimizing the aforementioned problems means optimizing all processing steps to reduce their environmental impact and make them more sustainable, resulting in reduced effluent loads and energy and water consumption. Several variables can be addressed to optimize textile processes, such as process temperature, water requirements, and the chemical system used. It is imperative to find alternative processes that operate at a lower temperature, require less water, or in which harsh chemicals can be replaced with environmentally friendly, more sustainable, and safer products.

Focusing specifically on cotton, it remains one of the most prominent textile fibers and has regained importance due to the strong environmental impact of synthetic fibers. Among the different stages of cotton pretreatment (before dyeing) are desizing, mercerization, alkaline washing, and bleaching, some of which require intensive chemical treatment and the need for multiple washing stages in between.

Naturally occurring fibers, such as cotton, still contain coloring agents even after washing, and this color may be caused by naturally occurring pigments present in the fiber structure. This color can come from various contaminants that occur during the processing of natural fibers, such as oils and greases from processing equipment.

The bleaching process aims to eliminate all color contaminants found on the fibers, as well as other contaminants that have resisted previous pretreatment procedures (desizing, washing, etc.) such as bark residue from the cotton plant.

Currently, the main procedure used for cotton bleaching is oxidative bleaching with hydrogen peroxide.

Considering a typical oxidative bleaching procedure by exhaustion, it usually consists of the steps represented in Figure 1.

Conventional cotton bleaching provides an article with a whiteness suitable for subsequent dyeing stages and free of additional contaminants. However, it is important to note that this stage is carried out at a very high temperature, requiring a considerable amount of time and energy to achieve. It also involves several water baths, which represent a significant consumption of water, and the discarded water is contaminated with harsh chemicals, such as NaOH.

This chemical is used in substantial quantities in the bleaching process and is a major contributor to the pollution load in bleaching effluents. A high concentration of NaOH in water can result in toxic effects for wildlife. Furthermore, highly concentrated NaOH solutions (such as those used for textile bleaching) are also corrosive and irritating to the skin, eyes, and mucous membranes, increasing the risk of harmful accidents among textile industry workers.

From the perspective of worker safety in the textile industry, it is also important to note that hydrogen peroxide solutions at a concentration of 50% can also pose significant safety hazards, such as skin burns; eye injuries; and the possibility of rapid pressurization within tanks, pipes, pumps, and/or storage vessels, etc. Therefore, it would also be advantageous to be able to replace the handling of this chemical.

There are other traditional bleaching procedures that can be applied, but they are even more harmful than oxidative bleaching with hydrogen peroxide. Chlorine is known to be extremely toxic to the environment and consumers, while sodium hypochlorite is very dangerous to human health due to its attack effect, which can cause skin and lung damage. In its compound form, sodium hypochlorite is also highly toxic to bacteria and aquatic organisms.

The Institute of Technology has been exploring the possibility of enzymes for several years. Enzymes are protein catalysts produced by living cells that catalyze specific reactions. The use of enzymes in textile processes has received increasing interest due to the fact that enzymes are nontoxic, biodegradable, and environmentally friendly.

Many processes, such as desizing, washing, and lint-removing, can be achieved with these products. However, an industrially viable enzyme that can directly bleach cotton textiles has not yet been developed. Furthermore, it has not been possible to include enzymes in conventional bleaching processes because they are typically not stable under the intense pH, temperature, and oxidative conditions of these processes.

WO0200823386 relates to novel compositions for biobleaching coupled with stonewashing of indigo-dyed denim fabrics comprising a combination of glucose oxidase, catalases and cellulases in the ratio of 1.0:10.0:1.0 together with a sugar base, peroxide source and optional adjuvants, wherein the process is carried out under optimized conditions of neutral pH (6.5 - 7.0) and a temperature of 55°C.

Document CN103266495 discloses a method for pretreating a cotton-polyester blend textile material with a biological enzyme. The method comprises the steps of washing and bleaching, washing and drying, and is characterized in that the washing and bleaching step comprises the sub-step of adding the cotton-polyester blend textile material to a washing and bleaching solution to undergo washing and bleaching, wherein the mass ratio of the cotton-polyester blend textile material to the washing and bleaching solution is (1:10)-(1:20); the temperature is controlled to be 50-60°C; the treatment time is 30-90 minutes; and the washing and bleaching solution comprises the following components in weight percentage: 2.5-3.5% of composite biological enzyme, 5-10% of hydrogen peroxide, 1-2% of tetraacetylethylene diamine, 0.1-0.3% of sodium cocoamphoracetate, 0.1-0.3% of ferrous sulfate and the balance water. The method has the advantages of desizing and bleaching in one bath, mild treatment conditions, little damage to the textile material and short treatment time. Additional bleaching processes are disclosed in WO-A-03/002810, US-A-2012/015860 and WO-A-2017/093677.

These facts are disclosed in order to illustrate the technical problem addressed by this disclosure.

Overview

In order to optimize and minimize the environmental impact of one of the most common cotton processing steps, oxidative bleaching, an alternative pretreatment procedure has been developed that bleaches textiles using less water, less energy, and less harsh chemicals.

The process of the present disclosure is a simplified treatment that results in a textile material that retains cotton characteristics and exhibits improved handling and hydrophilicity and a cleaner, smoother surface than conventionally bleached cotton.

A bleaching process was developed to save resources and increase the quality of the treated textile material, as well as water and energy consumption.

Additionally, the process of the present disclosure reduces the chemical load used, specifically eliminating the use of NaOH and including more sustainable versions of the auxiliary chemicals used.

The chemicals involved were the following:

Wetting agent - Based on naturally derived ethoxylated alcohols. It is silicone-free and complies with GOTS 5.0:2017 standards.

Enzyme combination - A specific enzyme combination, specifically developed for the process of the present invention, that produces a final product with good hydrophilicity and a soft feel. It contains at least three of the following enzymes: alpha-amylase, endoglucanase, beta-amylase, pectate lyase, cellulase, and lipase.

Peroxide donor - A solid compound that, reinforced by a combination of products, acts as a peroxide donor. The peroxide donor is selected from the following list: sodium percarbonate, sodium perborate, or a mixture thereof.

Bleach activator - It is a combination of salts that works as a specific activator for bleaching at lower temperatures.

Sequestering and dispersing agent - It is a biodegradable sequestering and dispersing agent based on a mixture of hydrocarboxylic acids. It is APEO-free and approved according to the GOTS 5.0:2017 standard.

Catalase - This is an enzyme commonly used to remove residual hydrogen peroxide after bleaching. One aspect of the present disclosure relates to a method for bleaching textile materials comprising the following steps:

prepare a first water bath with a wetting agent and the textile material,

in which the bath is heated to a first temperature up to a maximum of 40-60°C,

and the bath pH is at a maximum of pH 5.5-8;

adding an enzyme combination to the bath, wherein the enzyme combination comprises at least 3 of the following enzymes: alpha-amylase, beta-amylase, pectate lyase, cellulase, endoglucanase, lipase;

maintain the first bath temperature during the enzymatic reaction;

add a peroxide donor and a bleach activator to the bath;

heating the bath to a second temperature of at least 75°C for the peroxidation reaction, in which the peroxide donor is at 10 to 15 g/l,

in which the concentration of bleaching activator is from 1 to 3 g/l;

wherein the peroxide donor is sodium percarbonate, sodium perborate or a mixture thereof.

In one embodiment to obtain better results, the method may further comprise the following steps:

flush the water bath;

remove chemical residues from textile material.

In one embodiment to obtain better results, the method may further comprise the following steps:

Subject the textile material to a second bath at a minimum of 60°C to improve residue removal; drain the bath water.

In one embodiment to obtain better results, the method may further comprise the following steps:

prepare an additional water bath with a sequestering and dispersing agent, and the textile material,

in which the bath is heated to a temperature of up to a maximum of 60°C,

and the bath pH is at a maximum of pH 8;

maintain the first bath temperature during the reaction of the component.

In one embodiment to obtain better results, the method may further comprise the following steps:

Add a catalase solution to the third bath, maintaining the first bath temperature during the catalase reaction.

In one embodiment, to obtain better results, the duration of the enzymatic reaction is at least 30 minutes, preferably from 30 minutes to 1 hour, more preferably 45 minutes.

In one embodiment for best results, the second bath temperature is from 75-90°C, preferably 80°C.

In one embodiment to obtain better results, the duration of the peroxidation reaction is at least 5 minutes, preferably from 5-20 minutes, more preferably 10 minutes.

In one embodiment for best results, the temperature of the second bath is from 60-90°C, preferably 70°C.

In one embodiment for best results, the duration of the wash is at least 5 minutes, preferably from 5-20 minutes, more preferably 10 minutes.

In one embodiment for best results, the temperature of the third bath is from 25-60°C, preferably 40°C.

In one embodiment, for best results, the duration of washing with the sequestering and dispersing agent is at least 5 minutes, preferably from 5-15 minutes.

In one embodiment, for best results, the duration of the catalase reaction is at least 10 minutes, preferably from 10-30 minutes.

In one embodiment for best results, the enzyme combination is:

alpha-amylase, endoglucanase, cellulase;

alpha-amylase, endoglucanase, pectate lyase;

alpha-amylase, endoglucanase, lipase;

endoglucanase, beta-amylase, pectate lyase;

endoglucanase, beta-amylase, cellulase;

endoglucanase, beta-amylase, lipase;

beta-amylase, pectate lyase, cellulase;

beta-amylase, pectate lyase, lipase;

beta-amylase, cellulase, lipase;

pectate lyase, cellulase, lipase.

In one embodiment, to achieve better results, the enzyme combination further comprises oxidoreductase. In one embodiment, to achieve better results, the bath ratio of textile material to water is from 1:5 to 1:40; preferably 1:10 to 1:20.

In one embodiment for best results, the concentration of wetting agent is from 0.5 - 5% (w/w), preferably 1 - 2% (w/w).

In one embodiment for best results, the concentration of enzyme combination is from 0.5 - 5% (w/w), preferably 1 - 2% (w/w).

In one embodiment for best results, the sequestering and dispersing agent concentration is from 0.5 - 3 g/l, preferably 0.5 -1 g/l.

In one embodiment for best results, the catalase concentration is from 0.2 - 2 g/l.

In one embodiment for best results, the wetting agent is ethoxylated isotridecanol.

In one embodiment for best results, the bleach activator is a manganese salt.

In one embodiment for best results, the sequestering and dispersing agent is 3-hydroxy-3-carboxy-1,5-pentanedioic acid.

Another aspect of the present disclosure relates to a bleached textile material obtainable by the process described in the present disclosure in which the weight loss is lower than that of the conventional process, which is less than 4.5%.

In one embodiment for best results, the textile material is a natural yarn textile material, preferably a cotton textile material.

Another aspect of the present disclosure also relates to an article comprising the textile material described in the present disclosure.

Among the advantages of the process of the present invention are significant savings in terms of resource consumption, specifically:

• In one embodiment to achieve better results, the maximum temperature reached was 80°C, avoiding the need to heat the system an additional 20°C.

• By achieving the optimal temperature for each phase, which means using different temperatures, all below 100°C, there is no need to maintain the system at 100°C throughout the entire procedure.

• The process of the present invention makes it possible to obtain a white article with three water baths. Compared to the example shown in Figure 1, two water baths can be saved, taking into account the central wash and lint-removing baths. If 1 ton of cotton textile is bleached at a bath ratio of 1:10, eliminating two baths means a saving of 20,000 liters in water consumption, i.e., 20 liters of water per 1 kg of cotton.

• The chemical system used has been designed to present more sustainable products and avoid the need for harsh chemicals such as caustic soda, thereby reducing the effluent load of polluting species.

• The process of the present invention is also advantageous in terms of productivity since the total process time can be reduced.

Brief description of the drawings

The following figures provide preferred embodiments to illustrate the invention and should not be construed as limiting the scope of the invention.

Figure 1: Schematic representation of an embodiment of a process for oxidative bleaching of cotton. Figure 2: Schematic representation of an embodiment of one of the processes of the present subject matter. Figure 3: Schematic representation of an embodiment of one of the processes of the present subject matter: hydrophilicity: a) dispersion of the drop on a textile material treated with the common process for oxidative bleaching of cotton; b) dispersion of the drop on a textile material treated with the process of the present subject matter, the drop is wider and more regular, which means that the textile material has higher hydrophilicity.

Figure 4: Schematic representation of an embodiment of one of the methods of the present subject matter: a) perceptible raised fibers in the textile material treated with the common method for oxidative bleaching of cotton; b) cleaner and smoother surface of the textile material treated with the method of the present subject matter.

Figure 5: Schematic representation of an embodiment of one of the possible methods of the present invention: color yield for a light pink dye. Comparison of the same dye on a textile treated with the common method for oxidative bleaching of cotton (A) and a textile treated with the method of the present subject matter (B); spectrophotometric reading of both samples (C) and result for the color difference (DE).

Figure 6: Schematic representation of an embodiment of one of the possible methods of the present invention: for a salmon-colored dye. Comparison of the same dye on a textile treated with the common method for oxidative bleaching of cotton (A) and a textile treated with the method of the present subject matter (B); spectrophotometric reading of both samples (C) and result for the color difference (DE).

Figure 7: Schematic representation of an embodiment of one of the possible methods of the present invention: brown dyeing. Comparison of the same dye on a textile treated with the common method for oxidative bleaching of cotton (A) and a textile treated with the method of the present subject matter (B); spectrophotometric reading of both samples (C) and result for the color difference (DE).

Detailed description

The process of the present disclosure is an alternative pretreatment process that achieves textile bleaching using less water, less energy, and fewer harsh chemicals. It minimizes the environmental impact of one of the most common cotton processing steps: oxidative bleaching. The process of the present disclosure is a simplified treatment that results in a textile that retains cotton characteristics and exhibits improved handling and hydrophilicity, and a cleaner, smoother surface than conventionally bleached cotton.

In one embodiment, the present disclosure is used to bleach all 100% cotton articles used as raw material for the textile industry.

In one embodiment, the conventional process described in Figure 1 consists of the following steps: first water bath adding a detergent, a sequestering and stabilizing agent, an anti-wrinkle agent, 3 g/l of 50% NaOH and 3 g/l of H2O2200 vol;

temperature increase up to 100°C, treating the textile material for at least 30 minutes;

water discharge;

Washing with water containing a sequestering agent at a temperature of 70°C for 10 minutes; water discharge;

new washing stage with water at 60°C for 10 minutes;

water discharge;

new water bath at 40°C with addition of acetic acid for neutralization;

Run for 5 minutes and check pH, if necessary, adjust to the range of 6.5 - 7; add a catalase solution (an enzyme that will degrade hydrogen peroxide to prevent its interference with the dye) and run for an additional 15 minutes;

water discharge.

If an anti-lint treatment is required (for a cleaner surface and to reduce the textile's tendency to lint), an additional water bath is required. This is typically carried out at 50–60°C, pH 5–8, for 30–90 minutes, depending on the cellulase-based product (neutral or acidic cellulase) used. In this case, to inactivate the enzyme, it is mandatory to increase the temperature to 80°C for 10 minutes or to increase the pH by adding Na2CO3.

In one embodiment, the method of the present disclosure may comprise the following steps: obtaining a bath with the textile material to be bleached comprising water in a bath ratio of from 1:5 to 1:40, 0.5 - 5% of a wetting agent and setting the temperature to 40 - 60°C;

When the temperature is close to the set point, check that the pH is in the range of 5.5 - 8, add a 0.5 - 5% enzyme combination and run the procedure for 30-60 min;

add 10-15 g/l of a peroxide donor and 1-3 g/l of a bleach activator;

set the temperature to 75 - 90°C and run the procedure for 5 - 20 minutes;

discharge the water;

washed with water at 60 - 90°C for 5-20 minutes;

discharge the water;

new water bath at 25 - 60°C with the addition of 0.5 - 3 g/l of a sequestering and dispersing agent;

run for 5-15 min and check that the pH is 5-8;

add a catalase solution and run for 10 - 30 minutes;

discharge the water.

In one embodiment, considering an initial water temperature of 30°C, a machine with a heating and cooling rate of 4°C/min, a machine that takes 5 minutes to fill and 5 minutes to drain the water and optimized process conditions, the bleaching process is reduced from 148 min with the conventional process to 135 min with the process of the present disclosure, which means a reduction of approximately 9% in the process time.

Table 1: Comparison between 100% cotton knitted textile material bleached according to the conventional method and according to the process of the present disclosure

Table 2: Results of effluent analysis after conventional bleaching and the process described herein by depletion.

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Table 3: Effluent analysis results after conventional bleaching and the procedure of the present disclosure by continuous application (padded-steamed).

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In addition to the reduction in environmental impact due to resource savings, which has already been described, the effluents generated by the process of the present disclosure show reduced values for virtually all effluent analysis parameters, specifically BOD and COD, as shown in Tables 2 and 3.

The overall color difference can be calculated by spectrophotometric reading and is expressed as the DE value, obtained based on the comparison between samples that were subjected to conventional bleaching and samples treated by the process of the present disclosure. Conventional values for color tolerance accepted by companies in the industry are usually < 0.5.

Spectrophotometric analysis of the dyed samples shows DE values between 0.52 and 0.84, which can be attributed to the slight differences in the level of whiteness obtained in the samples after bleaching. This means that the color performance of samples subjected to the process of the present disclosure is not exactly the same, but is close enough to that of conventionally bleached samples, and therefore, it is expected that it will be easy to adjust the dyeing formulas. In some cases, this difference in color will possibly mean the need to use less dyestuff.

In conclusion, in terms of the characteristics of the final article, the process of the present disclosure is a perfectly viable option to replace the conventional bleaching process, given that the final article is softer, smoother, with a cleaner surface, improved hydrophilicity, and lower weight loss. Although there appears to be some variation in color performance, dyeing formulas are expected to be easy to adjust. When the variation in color performance is evaluated against all the benefits and advantages of the process of the present disclosure, it can be considered a reasonable adaptation.

Furthermore, from an environmental perspective, the method of the present disclosure allows for significant savings in water, energy and time consumption and results in less polluted effluents.

The term “comprising,” whenever used herein, is intended to indicate the presence of the features, integers, steps, components mentioned, but not to exclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

Those of ordinary skill in the art will appreciate that, unless otherwise indicated herein, the particular sequence of steps described is illustrative only and may be varied without departing from the disclosure. Thus, unless otherwise indicated, the steps described are in an unordered manner, meaning that, where possible, the steps may be performed in any convenient or desirable order.

Furthermore, it should be understood that the disclosure encompasses all variations, combinations, and permutations in which one or more limitations, elements, clauses, descriptive terms, etc., of one or more of the claims or relevant portions of the description are incorporated into another claim. For example, any claim dependent on another claim may be modified to include one or more limitations found in any other claim dependent on the same base claim.

Furthermore, where claims refer to a composition, it is to be understood that methods of using the composition for any of the purposes disclosed herein are included, and methods of making the composition according to any of the methods of making disclosed herein or other methods known in the art are included, unless otherwise indicated or unless it is apparent to one of ordinary skill in the art that a contradiction or inconsistency will arise.

Where ranges are provided, the endpoints are included. Furthermore, it should be understood that, unless otherwise indicated or unless apparent from the context and/or the understanding of one of ordinary skill in the art, values expressed as ranges may take any specific value within the ranges recited in different embodiments of the invention, up to one-tenth of a unit of the lower limit of the range, unless the context clearly dictates otherwise. It should also be understood that, unless otherwise indicated or apparent from the context and/or the understanding of one of ordinary skill in the art, values expressed as ranges may take any sub-range within the given range, wherein the endpoints of the sub-range are expressed to the same degree of precision as one-tenth of a unit of the lower limit of the range.

The above-described embodiments may be combined.

The following claims further set forth particular embodiments of the disclosure.

Claims (13)

i. Procedure for bleaching textile materials comprising the following stages: prepare a first water bath with a wetting agent and the textile material; wherein the first water bath is heated to a first temperature up to a maximum of 40-60°C and the pH of the bath is at a maximum of pH 5.5 - 8; adding an enzyme combination to the bath, wherein the enzyme combination comprises at least 3 of the following enzymes: alpha-amylase, beta-amylase, pectate lyase, cellulase, endoglucanase, lipase; maintaining the first bath temperature during the enzymatic reaction; add a peroxide donor and a bleach activator to the bath; heating the bath to a second temperature of at least 75°C for the peroxidation reaction; in which the peroxide donor concentration is from 10 to 15 g/l, in which the concentration of bleaching activator is from 1 to 3 g/l; wherein the peroxide donor is sodium percarbonate, sodium perborate or a mixture thereof. 2. Method according to the preceding claim, further comprising the following steps: flush the first water bath; remove chemical residues from textile material; optionally subject the textile material to a second water bath of a minimum of 60°C to improve residue removal; optionally flush out the bath water; optionally preparing an additional water bath, with a sequestering and dispersing agent, and the textile material, wherein the bath is heated to a temperature up to a maximum of 60°C, preferably 40°C - 50°C, and the pH of the bath is at a maximum of pH 8, maintaining the first bath temperature during the reaction time; optionally add a catalase solution to the third bath, maintaining the first bath temperature during the catalase reaction. 3. A method according to any preceding claim, wherein the first bath temperature is preferably 60°C and the pH of the first bath is preferably 6.0-6.5; and wherein the second bath temperature is from 75 to 90°C, preferably 80°C and wherein the second water bath temperature is from 60 to 90°C, preferably 70°C and wherein the third bath temperature is from 25 to 60°C, preferably 40°C. 4. Method according to any of the preceding claims, wherein the duration of the enzymatic reaction is at least 30 minutes, preferably from 30 minutes to 1 hour, more preferably 45 minutes. 5. Method according to any of the preceding claims, wherein the duration of the peroxidation reaction is at least 5 minutes, preferably from 5 to 20 minutes, more preferably 10 minutes. 6. Method according to any of the preceding claims, wherein the duration of the washing is at least 5 minutes, preferably from 5 to 20 minutes, more preferably 10 minutes. 7. Method according to any of the preceding claims, wherein the duration of washing with the sequestering and dispersing agent is at least 5 minutes, preferably from 5 to 15 minutes. 8. Method according to any of the preceding claims, wherein the duration of the catalase reaction is at least 10 minutes, preferably from 10 to 30 minutes. 9. Method according to any of the preceding claims, wherein the combination of enzymes is: alpha-amylase, endoglucanase, cellulase; alpha-amylase, endoglucanase, pectate lyase; alpha-amylase, endoglucanase, lipase; endoglucanase, beta-amylase, pectate lyase; endoglucanase, beta-amylase, cellulase; endoglucanase, beta-amylase, lipase; beta-amylase, pectate lyase, cellulase; beta-amylase, pectate lyase, lipase; beta-amylase, cellulase, lipase; pectate lyase, cellulase, lipase; optionally comprising oxidoreductase. 10. A method according to any of the preceding claims, wherein the bath ratio of textile material to water is from 1:5 to 1:40; preferably from 1:10 to 1:20. 11. Method according to any of the preceding claims, wherein The concentration of wetting agent is from 0.5 to 5% (w/w), preferably from 1 to 2% (w/w), Optionally, the concentrations of sequestering and dispersing agent are from 0.5 to 3 g/l, preferably from 0.5 to 1 g/l. 12. Method according to any of the preceding claims, wherein the concentration of enzyme combination is from 0.5 to 5% (w/w), preferably from 1 to 2% (w/w) and/or the concentration of catalase is from 0.2 to 2 g/l, preferably from 0.5 to 1 g/l. 13. Method according to any of the preceding claims, wherein The wetting agent is ethoxylated isotridecanol, the bleach activator is a manganese salt, the sequestering and dispersing agent is 3-hydroxy-3-carboxy-1,5-pentanedioic acid.