DE1144675B - Process for bleaching fibers of all kinds or yarns, woven or knitted fabrics made therefrom - Google Patents

Description

GERMAN

PATENT OFFICE

D 23751 IVc / 8i

REGISTRATION DATE: SEPTEMBER 5, 1956

NOTICE THE REGISTRATION ANDOUTPUTE EDITORIAL:

MARCH 7, 1963

It is known to use monopersulphates for bleaching textiles. It has been adjusted solutions of these salts with sodium carbonate to a _pH value of 10.7. Such solutions have a good bleaching effect, but they decompose with the release of oxygen so quickly that use causes difficulties.

It has now surprisingly been found that for the bleaching and bleaching washing of fibers of all kinds or yarns, woven or knitted fabrics made therefrom, solutions which contain monoperoxy acids, such as sulfomonoperic acid or phosphorus monoperic acid, their salts or compounds, can be used with excellent results concern transmits that the starting _pH value is adjusted of these solutions to about 11.0 or more. Such solutions are several times more resistant without the bleaching effect being damaged. Experiments have shown that an aqueous solution containing per liter 2.5 g of potassium monopersulfate, and is adjusted to a _pH value of 9.25 with sodium carbonate, sodium silicate and borax, at 5O ⁰ C even in the absence of the bleaching material after 5 minutes contains only 67%, after 15 minutes only 32% and after 60 minutes only 3% of the initially present active oxygen. In contrast, loses a solution of 2.5 g of potassium monopersulfate in the liter of water, which is adjusted with caustic soda to a _pH-value 12,2, after 15 minutes only 3%, and after 60 minutes only 13% of the active oxygen.

It is advantageous to use at least 2 equivalents of alkali metal hydroxide per mole of monoperoxy acid. But in many cases it is also possible, in addition to the alkali metal hydroxide also a alkali carbonate, such as sodium carbonate to consult to adjust the p _H -value.

Further research has shown that the bleaching effect can be improved if one a solution of the type described used, which also contains halogen ions, as for example is achieved by adding table salt.

The solutions according to the invention can contain buffer substances known per se, such as sodium silicate, sodium phosphate or borax, can be added.

In carrying out the bleaching process of the _pH-value decreases the bleaching solutions. It has been found that it is advantageous in many cases to accelerate this reduction of the p _H -value during the bleaching process and to facilitate such. B. by adding buffer substances or acids. As a result, particularly good bleaching effects are achieved towards the end of the bleaching process, and there is a method for bleaching fibers of all kinds

or yarns, fabrics made therefrom

or knitted

Applicant:

German gold and silver refinery

formerly Roessler, Frankfurt / M., Weißfrauenstr. 9

Dr. Karl Dithmar and Dr. Elfriede Naujoks,

Frankfurt / M., Have been named as inventors

better utilization of the active oxygen of the monoperoxy acid instead.

Bleach solutions of the type described can be created by adding the constituents individually to the solution produce. With good success, however, the procedure can also be used to produce the solution required solid components, d. H. the salt of monoperoxy acid, caustic alkalis and optionally Alkali carbonates and buffer substances and chlorides, in the solid state, can be mixed and dissolved together. These solid mixtures are characterized by a good shelf life.

With the simultaneous presence of detergent substances in the bleaching solutions, in addition to the bleaching effect achieved a washing effect.

The bleaching process can be carried out at relatively low temperatures while protecting the fibers, z. B. at 50 to 80 ° C or at room temperature.

example

Four times 10 kg of cotton fabric were each in 2501 bleaching bath with the following Substances, the quantity of which relates to 1 1 bath, treated at 50 ° C for 1 hour. It showed up at the higher concentration of experiments c) and d) had a slightly better bleaching effect than the lower one Active oxygen concentration. Experiments b) and d), which were carried out with the addition of NaCl were better in whiteness than the comparatively bleached tests without NaCl.

309 538/386

Temperature 50 ° C Dodecyl sulfate
caustic soda
KHSO ₅ 3 Ph end 1 144 675 5 4th 15 minutes 30 minutes 60 minutes 2.5 g
Ug
2.5 g Dodecyl sulfate
caustic soda
KHSO ₅
NaCl 64% 47% 28% 2.5 g
Ug
2.5 g
5.0 g Dodecyl sulfate
caustic soda
KHSO ₅ Beginning Still from 65% 48% 29% 5.0 g
2.4 g
5.0 g Dodecyl sulfate
caustic soda
KHSO ₅
NaCl I 11.7 0 minutes 57% 44% 27% 5.0 g
2.4 g
5.0 g
5.0 g • 11.5 100 o / o = 0.23 g
per liter 54% 38% 22% \ 11.7 10.2 100 % = 0.23 g
per liter active oxygen initially present
found iodometrically after Liquor ratio 1:25 • - 11.5 10.0 100 o / o = 0.46 g
per liter Minutes 11.25 100 % = 0.46 g
per liter 76% a) 10.85 79% b) 750/0 c) 67% d)

Claims (4)

PATENT CLAIMS: 1. A process for the bleaching of all types of fibers or bleaches that solutions are used which have produced therefrom yarns, fabrics or knitted fabrics with alkaline solutions of monoperoxy acids or their salts, characterized in that an initial _pH value of about 11.0 or more . 2. The method according to claim 1, characterized in that the bleaching solutions per mole of Monoperoxy acid contain at least 2 equivalents of alkali hydroxide. 3. The method according to any one of claims 1 and 2, characterized by the use a bleach solution that still contains halogen ions. 4. The method according to any one of claims 1 to 3, characterized in that the solution after the start of the bleaching process, substances are added that reduce the pg value. Considered publications:
German Patent Nos. 561481, 636 258;
Chemisches Centralblatt, 1939 I, pp. 4269 to 4270, Ref .; Swiss patent specification No. 199 419. When the application was announced, a test report and six tables were displayed.