EP1655409A1 - Method for the treatment of silver-containing textile substrates - Google Patents

Abstract

The bleaching is carried out after the block-cold-staying with the peracetic acid (0.05-2 Wt %) splitting off agent of nonanoyloxybenzenesulfonic acid/tetraacetylethylenediamine for duration of (10-30 h) in presence of an activators and detergents at 30-70[deg]C and at pH of (6-7). The textile cellulose is knitted, coated or bonded fabrics, stable, acetate, cuprous or alginate fibers, polyamide, polyacrylnitrile, polyurethane, polyester, filaments and/or yarns.

Description

The invention relates to a process for the treatment of silver-loaded textile substrates or of textile substrates to which silver is adsorbed or absorbed, the textile substrate being bleached with peracetic acid.

Fibers with silver are increasingly used in the medical and wellness sector. They are characterized by a high color of the raw material. Textile products in the color range of gray and beige, and after dyeing dull shades are the result. Such fibers must therefore be washed and bleached. Washing refers to prewashing and washing to remove excess chemicals, textile auxiliaries and dyes in the textile finishing industry, and washing of final household and laundry products. Bleaching is understood to mean all textile finishing processes that deal with the oxidative destruction of coloring substances.

Usually, hydrogen peroxide is used for this purpose. The use of peracetic acid as a bleaching agent has been very hesitant in the paper industry. In textile finishing processes, such processes are used only to achieve the highest neutral whites, such as in the production of white scale bars. In household linen and industrial laundry, the use of peracetic acid-releasing agents are state of the art, since whiteness improvements can be achieved without fiber damage.

A process for bleaching with peracetic acid is described in DE 4035053 A1, where cellulosic materials or cellulosic materials, in particular cotton, are mentioned as fibrous materials and the bleaching is carried out at a pH of 1 to 4.

Many publications of the 90s describe the behavior of peracetic acid in the temperature range up to 120 ° C and a pH of 5 to 8 and the resulting whiteness and fiber damage for different fibers. In textile practice, peracetic acid was unable to prevail over hydrogen peroxide. Simpler, more universal and significantly cheaper process engineering conditions for the hydrogen peroxide bleaching caused peracetic acid to almost completely recede in the area of industrial production.

The situation is similar with sodium chlorite bleach, which is still used in part for the bleaching of polyester, and with the reductive bleaching process.

When bleaching silver-loaded textile substrates with hydrogen peroxide, it has been found that the pulp catalytically decomposes hydrogen peroxide and causes fiber damage and no increase in whiteness. Sodium chlorite behaves similarly. Reductive bleaching processes result in poor white grading.

The invention was therefore based on the object of providing a simple method for bleaching textile substrates with silver.

This object is achieved by a method for the treatment of silver-loaded textile substrates, characterized in that the textile substrate is bleached with peracetic acid.

The treatment in the sense of the description comprises the refining of textile substrates after their preparation and a subsequent washing. When finishing textile substrates, these can be subjected to a wide variety of known process stages. Refinement includes all processing operations of textile substrates after leaving the raw material from weaving, knitting, knitting or fiber production and nonwoven production to the finished finishing. The processing operations performed during refining are dependent on the one used Textile substrate and the desired effect. Generally, refining may include wet finishing such as bleaching, mercerizing, carbonizing and tumbling, and drying equipment such as decatizing, calendering, pressing, roughing, shearing and singeing. In the method according to the invention it is preferred to carry out a mechanical / thermal treatment, such as singeing, optionally bleaching, wet finishing, such as mercerising, bleaching, and optionally dyeing, drying and finishing.

Bleaching in the sense of the present description encompasses both the washing and the bleaching of textile substrates. Washing is understood here to mean the pre-washing and washing for removing excess chemicals, textile auxiliaries and dyes in the textile finishing industry and the washing of optionally used final products in the household and in laundries. Bleaching is understood to mean all textile finishing processes that deal with the oxidative destruction of coloring substances.

The silver-loaded textile substrates include all textile materials made from natural or chemical fibers or filaments and the fibers and filaments themselves. Preferably, the textile substrates are selected from woven, knitted, crocheted, nonwoven, fibers such as staple fibers, filaments and / or yarns. The textile substrates may comprise any material suitable to produce them, such as cellulose, such as lyocell, modified cellulose, actetate, cupro, alginate fibers (made from sodium alginate extract of algae), polyamide, polyacrylonitrile, polyurethane, triacetate, polyester, modified polyester, and polyolefin. The textile substrate preferably comprises cellulose or modified cellulose, such as cotton, rayon, viscose and lyocell, ie a cellulosic material which is prepared in a manner known per se by dissolving cellulose in an amine oxide hydrate, preferably N-methylmorpholine N-oxide monohydrate (NMMO ), and introducing the solution into a non-solvent for the cellulose, preferably water, whereby the cellulosic body precipitates in the non-solvent. As a result, so-called lyocell fibers are obtained, the cellulose forming the shaped body and its hydroxyl groups not having additional functional groups, in particular sulfonic acid or carboxyl groups, etc. is modified. To prevent the fibrillation of lyocell fibers, they can be crosslinked during the manufacturing process or in a textile post-processing step on the hydroxyl groups of the cellulose to prevent fibrillation.

The textile substrate which can be used according to the invention can also comprise a plurality of materials, such as natural and / or synthetic polymers, which can either be added to the spinning composition or as bi- and multicomponent fibers in side-by-side, island-in-the-sea or sheath core configuration.

The material forming the textile substrate may contain further additives. Particularly preferred as an additive, in particular when the material is cellulose or modified cellulose, especially lyocell, is a vegetable and / or animal material. The vegetable and / or animal material is preferably a material from marine plants or marine animals.

The material from marine plants is preferably selected from the group consisting of algae, kelp and seaweed, in particular algae. Examples of algae include brown algae, green algae, red algae, blue-green algae or mixtures thereof. Examples of brown algae are Ascophyllum spp., Ascophyllum nodosum, Alaria esculenta, Fucus serratus, Fucus spiralis, Fucus vesiculosus, Laminaria saccharina, Laminaria hyperborea, Laminaria digitata, Laminaria echroleuca and mixtures thereof. Examples of red algae include Asparagopsis armata, Chondrus cripus, Maerl beaches, Mastocarpus stellatus, Palmaria palmata and mixtures thereof. Examples of green algae are Enteromorpha compressa, Ulva rigida and mixtures thereof. Examples of blue-green algae are Dermocarpa, Nostoc, Hapalosiphon, Hormogoneae, Porchlorone. A classification of algae is the Textbook of botany for colleges E.Strasburger; F.Noll; H.Schenk; AFW chimera; 33rd edition Gustav Fischer Verlag, Stuttgart-Jena-New York; 1991.

The material from marine plants can be obtained in a known manner.

First, the material is harvested from seaweeds. The harvested material can be further processed in various ways. The material from marine plants can be dried at temperatures up to 450 ° C and comminuted using ultrasound, wet ball mills, pin mills or counter-rotating mills, whereby a powder is obtained, which may optionally also be performed for classification via a cyclone stage. A powder thus obtained can be incorporated into the material which can be used according to the invention, preferably cellulose or modified cellulose, such as lyocell.

In addition, this seaweed material powder may be additionally subjected to an extraction process, for example, with steam, water or an alcohol such as ethanol to obtain a liquid extract. This extract is also useful as an additive to the material useful in this invention.

The harvested seaweed material may also be subjected to cryo-crushing. It is comminuted at -50 ° C into particles with about 100 microns. If desired, the resulting material may be further comminuted to yield particles of about 6 to about 10 microns in size.

The material from the outer shell of marine animals is preferably selected from marine sediments, crushed shells of crabs or clams, lobsters, crabs, shrimp, coral.

The material from shellfish of marine animals, in the case of marine sediments, can be used directly. If material from the shells of crabs or clams, hummem, crabs, shrimp is used, it will be crushed.

It is also possible to use mixtures of material from marine plants and peels of marine animals and their extraction products. The quantitative ratio of material from marine plants and shells of marine animals is preferably 50 wt .-% to 50 wt .-%. Preferably, seaweed material is used in the invention.

It is also possible to use particles of the material from marine plants and / or shells of marine animals in the grain size range of 200 to 400 .mu.m, preferably 150 to 300 .mu.m. It is also preferable to use particles having small grain sizes, such as 1 to 100 μm, more preferably 1 to 5 μm. It is also possible to use particle size mixtures of uniform material or different algal material.

An example of a useful material from marine plants is a powder of Ascophyllum nodosum with a particle size of 95% <40 my, containing 5.7% by weight of protein, 2.6% by weight of fat, 7.0% by weight. fibrous constituents, 10.7% by weight of moisture, 15.4% by weight of ash and 58.6% by weight of hydrocarbons. It also contains vitamins and trace elements such as ascorbic acid, tocopherols, carotene, barium, niacin, vitamin K, riboflavin, nickel, vanadium, thiamine, folic acid, folinic acid, biotin and vitamin B12. In addition, it contains amino acids such as alanine, arginine, aspartic acid, glutamic acid, glycine, leucine, lysine, serine, threonine, tyrosine, valine and methionine.

The material from marine plants and / or shells of marine animals may be present in the material of the textile substrate, preferably cellulose or modified cellulose, in particular lyocell, in an amount of 0.1 to 30% by weight, preferably 0.1 to 15% by weight. , more preferably 1 to 8 wt .-%, in particular 1 to 4 wt .-%, based on the weight of the lyocell-shaped body, be present. In particular, when the lyocell-shaped body is in the form of a fiber, the amount of material from marine plants and / or shells of marine animals is preferably 0.1 to 15 wt .-%, in particular 1 to 5 wt .-%.

The continuous or discontinuous mixing, for example, of the cellulose and the material from marine plants and / or shells of marine animals may be carried out by apparatus and methods as described in WO 96/33221, US 5,626,810 and WO 96/33934.

The content of silver adsorbed on the textile substrate to be used in the present invention is preferably at least about 70 mg / kg, preferably at least about 200 mg / kg, more preferably at least about 500 mg / kg, especially at least about 1000 mg / kg, based on the total weight of the textile substrate. In particular, a textile substrate is used according to the invention which is antibacterial and / or fungicidal by the adsorption of silver.

In one embodiment of the method according to the invention, a vegetable and / or animal material, as described above, is added to a textile substrate, preferably cellulose or modified cellulose, in particular lyocell, and then the silver is adsorbed thereon. This achieves a very even distribution of the silver in the textile substrate which can be used according to the invention. This has the advantage that a large amount of silver can be introduced into the textile substrate.

The silver may be present on or in the textile substrate usable according to the invention in ionic form, in elemental form, in oxidic form or in any other form.

The loading of the textile substrate to be used according to the invention with silver can be carried out by immersing a prepared shaped body in a silver-containing aqueous solution, such as an AgNO ₃ solution, separating the silver-containing, aqueous solution and, if appropriate, washing and drying the resulting textile substrate. The loading procedures are carried out between 1 minute and several hours, depending on the area of application.

The textile substrate which can be used according to the invention can remain in the aqueous, silver-containing solution for up to about four hours. The aqueous silver-containing solution is preferably about 0.1 M in terms of the silver contained therein.

Without being bound by theory, it is believed that, for example, the silver is permanently attached to the phenolic groups and glucose components of the alumina and aldehyde groups of the algal glucose components can be oxidized to carboxyl groups. The chelating ability of algal material is exploited to produce complex compounds with silver. It is believed that silver is ring-surrounded as a central metal ion to form bonds of one or more phenolic groups (ions). However, it is also possible that the silver is present on the textile substrate in elemental form or oxidized, such as Ag ₂ O.

The textile substrate which can be used according to the invention can comprise, in addition to the textile substrate with silver, further substrates which are not loaded with silver.

The peracetic acid used in bleaching may preferably be selected from equilibrium peracetic acid, peracetic acid and / or peracetic acid eliminating agents prepared in situ from acetic anhydride and hydrogen peroxide in the bleaching bath, such as NOBS (sodium nonanoyloxybenzene sulfate) or TAED (tetraacetylethylenediamine) using activators, for example peroxides, such as H ₂ O ₂ or H ₂ O ₂ releasing agents.

Preferably, the bleaching in the process according to the invention at a pH of about 4 to about 7, in particular about 6 to 7, performed.

To bleach with peracetic acid from the textile substrate with silver can be resorted to commercial peracetic acid in the concentration of 15%. The concentration of peracetic acid in bleaching is preferred Bleaching bath about 0.5 wt% to about 4 wt%, more preferably about 1 wt% to about 3 wt%, more preferably about 1.12 wt% to about 3.36 wt% based on 1 l of the bleaching bath. More preferably, bleaching may also be carried out with a lower concentration of peracetic acid, preferably with an amount of 15% peracetic acid in the bleaching bath of from about 0.05% to about 2% by weight, more preferably about 0.1% by weight. % to about 1.5 wt%, more preferably about 0.1 wt% to about 1.2 wt%, more preferably about 0.1 to about 0.9 wt%. This corresponds to a preferred amount of peracetic acid to be used in the bleaching bath 15% from about 3 ml / l to about 133 ml / l, more preferably about 6 ml / l to about 100 ml / l, more preferably about 6 ml / l to about 80 ml in particular about 6 ml / l to about 60 ml / l.

Preferably, the bleaching is carried out at a temperature of about 15 to about 80 ° C, more preferably about 40 to about 80 ° C, more preferably about 40 to about 75 ° C, especially about 30 to about 70 ° C. The temperature may also be initially selected at about 30 to about 40 ° C and then, for example, at a rate of about 1 ° C / min. be heated to about 60 to about 80 ° C.

The bleaching may preferably be carried out by the pad cold dwelling method or by a full bath treatment.

The bleaching is preferably carried out in the pad-cold dwelling method for a period of about 10 to about 30 hours, in particular about 10 to about 24 hours and in the Vollbadverfahren about 15 min. to about 2 hours, more preferably about 30 minutes. until about 90 minutes.

Bleaching with peracetic acid from the textile substrate with silver can be carried out batchwise, semi-continuously or continuously. In the pad-cold process (semi-continuous), the textile substrate (piece goods and wide stock) is impregnated on the padder by applying concentrated bleaching liquor and then squeezing off the bleaching liquor excess. The textile substrate passes through a trough in which The concentrated bleaching liquor is then passed through two or more pairs of rollers that squeeze the fleet and transport the goods on. The textile substrate is then rolled up, the textile substrate roll wrapped in foil and left at room temperature under slow rotation until a uniform bleaching is achieved. Subsequently, the textile substrate is rinsed.

In the exhaust or full bath process, the textile substrate to be bleached is drawn through an aqueous bleach solution. In the exhaust process, the textile substrate is impregnated with the bleaching liquor, treated for a time tempered and then washed out. This process is carried out batchwise.

Preferably, the textile substrate is dyed after bleaching according to the method of the invention. Any conventional method and dye may be used for this purpose. In a particularly preferred embodiment, the textile substrate according to an embodiment of the method according to the invention is not subjected to wet treatment of the fabric with alkali after bleaching and before dyeing, since otherwise the built-in silver can increase the color of the textile substrates. It is also preferable to perform no treatments with strongly alkaline solutions during the dyeing and after-treatment of the dyeing.

Also, the textile substrate can be crosslinked with silver after bleaching. As a reactant crosslinker, for example, DMDHEU can be used.
The textile industry employs, for example, DMDHEU (DiMethylol-DiHydroxy-EthyleneUrea) as a reactant crosslinker to improve the properties of fibers and fabrics in order to improve the wrinkling properties of fabrics and fibers. Mostly DMDHEU is used with a catalyst mixture. This treatment achieves a chemical reaction in which 2 or more OH groups of the cellulose fibers react with polycondensing DMDHEU molecules. By this cross-linking of the fibers are the Limited possibilities of movement of the individual fiber and achieved overall better product properties.

In a further embodiment of the method according to the invention, the bleaching comprises bleaching the textile substrate with silver after use by household or industrial laundering.

The temperatures and residence times in bleaching in this embodiment are those commonly used in household and industrial laundries, such as at a temperature of about 30 to about 70 ° C. Bleaching, e.g. with TAED, in the household or industrial laundry is preferably carried out in the presence of activators and conventional detergents. TAED is commercially available in household detergents at a concentration of 2.5 to 15%. Also, the amount of detergent commonly used can also be doubled depending on the desired effect.

Furthermore, the present invention relates to the use of peracetic acid for bleaching textile substrates with silver, applying the same conditions as described above in relation to the method.

Surprisingly, it was found that when using peracetic acid, a significant increase in the whiteness was achieved. Fiber damage could not be detected.

Furthermore, it has been found that strong yellowing occurring during the finishing process, such as by a mercerizing process, can be eliminated by the use of peracetic acid and at the same time a further increase in whiteness occurs.

It was also determined that partial red colorations of the product due to environmental influences can be eliminated by peracetic acid treatment. An application of this knowledge is also given in the areas of household and industrial laundry. Here, the use of peracetic acid releasing agents, such as NOBS (sodium nonanoyloxybenzene sulfate) takes place or TAED (tetraacetylethylenediamine), etc. TAED develops its full effectiveness within a few minutes, depending on the activators used in the range of 40 to 60 ° C.

In the dyeing of these fibers, it has been found that the wet fastness level of the dyeings is comparable to other dyed cellulosic fibers, the light fastness level always remains behind that of comparable fibrous materials. In general, high-lightfast dyes should be selected and tested on the respective fiber types.

The method will be explained by way of examples.

example 1

• Sengen, Bleichen (Klotz - Kalt - Verweilverfahren), Mercerisieren, Bleichen (Klotz - Kalt - Verweilverfahren), Trocknen, Färben (Klotz - Kalt - Verweilverfahren), Trocknen, Appretieren, Kalandern.

A fabric made from cotton, SeaCell®, a cellulose fiber incorporated with algae and SeaCell®-Active, SeaCell® fiber, which is additionally loaded with silver, is to be processed into a high-quality pastel-colored bed linen. The following sequence of operations is required:

• Sinking, bleaching (pad - cold - dwelling), mercerising, bleaching (pad - cold - dwelling), drying, dyeing (pad - cold - dwelling), drying, finishing, calendering.

Rohgewebe

stark farbig

Sengen

leichte Erhöhung der Farbigkeit

Bleichen

akzeptabler Weißgrad, der geeignet ist zum Färben von hellen brillanten Pastelltönen

Mercerisieren

Verlust des Weißgrades und Erreichen einer Farbigkeit, höher als bei gesengtem Gewebe

Bleichen

verbesserter Weißgrad, der sehr gut geeignet ist zum Färben von hellen brillanten Pastelltönen

Färben

Auswahl von gut aufbauenden Farbstoffen mit guten bis sehr guten Lichtechtheiten

Trocknen

bei normalen Trockentemperaturen keine Weißgradbeeinflussung

Appretieren

zum Beispiel tritt beim Ausrüsten mit Vernetzern selbst bei einer Trockenvernetzung keine Verringerung des Weißgrades ein

Kalandern

keine Weißgradbeeinflussung.

It is a process for classic bedding equipment with an additional bleaching process. However, this is absolutely necessary because these fibers go through the following development, the color white:

gray fabric

strongly colored

singe

slight increase in color

bleaching

acceptable whiteness suitable for dyeing bright, brilliant pastel shades

mercerising

Loss of whiteness and reaching a color, higher than with tissue squeezed

bleaching

improved whiteness, which is very suitable for dyeing bright brilliant pastel shades

To dye

Selection of well-structured dyes with good to very good light fastness

dry

at normal drying temperatures no whiteness influence

glaze

For example, when curing with crosslinkers, even with dry crosslinking, there is no reduction in whiteness

calenders

no whiteness influence.

• Sengen, Mercerisieren, Bleichen (Klotz - Kalt - Verweilverfahren oder Vollbad), Färben (Klotz - Kalt - Verweilverfahren oder Vollbad), Trocknen, Appretieren, Kalandern

For economic reasons, the technology can be modified as follows.

• Sinking, mercerizing, bleaching (pad - cold - dwelling or full bath), dyeing (pad - cold - dwelling or full bath), drying, finishing, calendering

As usual in the textile finishing process, discontinuous as well as continuous processes can be used due to the existing technical equipment and the batch size.

The bleaching by means of peracetic acid is carried out as follows:

Vollbadverfahren

bath preparation:

1ml / l Lavotan RWS
2 g / l sodium pyrophosphate
10 to 30 ml / l peracetic acid 15%
adjusted to pH 6.5 with sodium hydroxide solution

Operation:

Inlet temperature 40 ° C
Heating to 75 ° C at 1 ° C / min
Treated at 75 ° C for 50 minutes,
Rinse 2x

Klotz-cold dwell bath approach:

3ml / l Lavotan RWS
2 g / l sodium pyrophosphate
40 to 80 ml / l peracetic acid 15%
pH, pH 6.5

squeezing pressure:

4 bar

dwell time:

16 to 24 h

wash:

Wide washing machine, as usual

The assortments have sufficient whiteness to achieve pure and brilliant shades of known type and they are less prone to discoloration in use.

The dyeing is carried out according to known technologies and with conventional dye classes. The treatment of strongly alkaline baths leads to an increase in the color of the textile substrates and must be avoided.

Badansatz:

bis 60 g/l Reaktantvernetzer, z.B. DMDHEU
bis 2 g/l Netzmittel
bis 30 g/l PE-Dispersion
bis 30 g/l Avivagemittel

Klotzen und Trocknen:

Maschine:

Spann-Trocken-Fixiermaschine

Abquetschdruck:

5 bar

Trockentemperatur:

120°C

Voreilung:

1 %

Kondensieren

Maschine:

Kondensiermaschine

Trockentemperatur:

145°C

Voreilung:

1 %

Verweilzeit:

4 min

The equipment with crosslinkers is done with the following bath batch:

bath preparation:

to 60 g / l Reaktantvernetzer, eg DMDHEU
to 2 g / l wetting agent
up to 30 g / l PE dispersion
up to 30 g / l of lubricant

Padding and drying:

Machine:

Spann-dry Fusing

squeezing pressure:

5 bar

Dry Temperature:

120 ° C

advance:

1 %

Condense

Machine:

Kondensiermaschine

Dry Temperature:

145 ° C

advance:

1 %

dwell time:

4 min

The end products made from these textile substrates are to be washed by the usual methods.

Household linen must contain detergents containing at least 10% TAED (tetraacetyl-ethylenediamine). If there is a clear discoloration towards red, the usual amount of detergent must be doubled.

TAED as a bleaching agent is offered in the following compositions % % % TAED 2.5 5 15 Sodium perborate monohydrate 10 15 45 zeolites 28 25 Sodium 20 20 40 Sodium silicate 4 4 PCAs 4 4 Wetting agent 15 15 enzymes 0.5 0.5 Optical brighteners 0.3 0.3 Sodium sulfate 9 5

In industrial laundry, wash in the presence of peracetic acid. Bleach concentration up to 10 ml / l peracetic acid can be used in the full bath be applied. The use of an equivalent amount of TAED or similar work as in household linen is possible.

Example 2 (bleaching with peracetic acid after the cold pad dwelling method) 2.1. Variation of the pH value and the residence time)

Material: cotton batiste Machine: Foulard, stay rotating Bath batch 1 (B1): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 50 ml / l peracetic acid 15% pH 3.15 Bath batch 2 (B2): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 50 ml / l peracetic acid 15% adjusted to pH 5.04 with NaOH Bath start 3 (B3): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 50 ml / l peracetic acid 15% adjusted to pH 6.02 with NaOH Badansatz 4 (B4, WBV 4): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 50 ml / l peracetic acid 15% adjusted to pH 6.7 with NaOH squeezing pressure: 4 bar Speed: 1 m / min dwell time: Sampling after 2 h, 5 h, 24 h wash: in a full bath, 2x 10 min. at 60 ° C, 1x 10 min. cold

Colorimetric determination (Table 1)

Whiteness CIE Bath batch 1, B1 Bath start 2, B2 Bath start 3, B3 Bath start 4, B4 Residence time 2h 32.5 35.0 37.3 38.8 Residence time 5h 37.6 40.2 41.5 44.3 Residence time 24h 42.6 48.0 49.9 50.9

The whiteness of the desized fabric was found to be 14.0. Table 1 above shows that a significant improvement in whiteness has been achieved. It can also be seen from Table 1 that the pH has an influence on the whiteness and the residence time is advantageously 5 h, better 24 h.

2.2. Variation of concentration

Material: Variant 4, singed, desized, mercerized Machine: Foulard, stay rotating Bath batch 1 (BK1): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 40 ml / l peracetic acid 15% adjusted to pH 6 - 6.5 with NaOH Bath start 2 (BK2): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 50 ml / l peracetic acid 15% adjusted to pH 6 - 6.5 with NaOH Bath batch 3 (BK3, BKM3): 3 ml / l Lavotan RWS 2 g / l sodium pyrophosphate 60 ml / l peracetic acid 15% adjusted to pH 6 - 6.5 with NaOH squeezing pressure: 4 bar Speed: 1 m / min dwell time: 24 hours wash: in a full bath, 2x 10 min. at 60 ° C, 1x10 min. cold

Colorimetric determination (Table 2)

Variation 4, singed, desized, mercerized (BK1 - BK3) Variation 4, singed, desaturated Bath batch 1 Bath start 2 Bath start 3 Bath start 3 Whiteness CIE 21.1 28.8 30.6 34.2

From the results of Table 2 it can be seen that the whiteness is improved with increased peracetic acid use. With an amount of more than 50 g / l peracetic acid, the whiteness only increases insignificantly. Similar results can be expected on non-mercerised tissue.

Claims (18)

Process for the treatment of silver-loaded textile substrates, characterized in that the textile substrate is bleached with peracetic acid. The method of claim 1, wherein the bleaching is carried out at a pH of about 4 to about 7. The method of claim 2, wherein the bleaching is carried out at a pH of about 6 to about 7. A method according to any one of the preceding claims wherein the concentration of 15% peracetic acid is from about 0.05% to about 2% by weight. A method according to any one of the preceding claims, wherein the bleaching is carried out at a temperature of about 15 to about 80 ° C. A method according to any one of the preceding claims, wherein the bleaching is carried out by the pad-cold dwell method for a period of about 10 to about 30 hours. Method according to one of the preceding claims, wherein the textile substrate is bleached discontinuously, semi-continuously or continuously. A method according to any one of the preceding claims, wherein the textile substrate is dyed after bleaching. A method according to claim 8, wherein after bleaching and before dyeing, no wet treatment of the textile substrate with alkali is carried out. Method according to one of claims 8 or 9, wherein no treatments with strongly alkaline solutions are carried out during the dyeing and after-treatment of the dyeing. The method of claim 1, wherein the textile substrate is bleached after use by household or industrial laundry. The method of claim 11, wherein the bleaching is carried out at a temperature of about 30 to about 70 ° C. A method according to any one of claims 11 or 12, wherein the bleaching is carried out in the presence of activators and conventional detergents. A method according to any one of claims 11 to 13, wherein the bleaching is carried out with a peracetic acid releasing agent such as TAED or NOBS. Method according to one of the preceding claims, wherein the textile substrate is selected from woven, knitted, crocheted, nonwoven fabrics, fibers, such as staple fibers, filaments and / or yarns. A method according to any one of the preceding claims, wherein the textile substrate is made of a material selected from cellulose, modified cellulose; Actetate, cupro, alginate fibers (made from sodium alginate extract of algae), polyamide, polyacrylonitrile, polyurethane, triacetate, polyester, modified polyester, and / or polyolefin. The method of claim 16, wherein the material is selected from cellulose which additionally contains a material from marine plants or marine animals. Use of peracetic acid for bleaching silver loaded textile substrates.