DE1291317B - Process for bleaching textiles - Google Patents

Description

The invention relates to bleaching processes which are used to remove stains from textiles • are suitable.

Inorganic persalts, ζ. Sodium perborate and sodium percarbonate are widely used in detergents to give them bleaching power. These persalts provide satisfactory bleaching when the detergent is used at the boil, but at lower temperatures their action is rather slow. This is a considerable disadvantage in view of the wide use of operating at temperatures of about 50 to 6O ⁰ C washing machines, for washing with persalzhaltigen cleaning agents at these temperatures are no highly effective bleaching in the normal washing period. The invention is concerned with bleaching processes in which persalts are activated so that more effective bleaches can be achieved at these relatively low temperatures.

It has been found that certain organic nitrogen compounds, which are constitutionally amides, have an activating effect on the bleaching capacity possess inorganic persalts at these temperatures. Presumably it reacts when loosening it The hydrogen peroxide released from the persalt in water and the amide form a stronger one Bleaching agent as hydrogen peroxide and thus favors bleaching at low temperatures. the A nitrogen compound's ability to achieve this effect depends at least in part on its electronic Properties of their molecule. Changes in the substituents in the molecule can be significant affect the behavior of the amide in the bleaching process.

Amides suitable as activators can be characterized simply and expediently by a test in which a persalt and the amide are heated together in water and the strong bleaching agent produced in this way is classified according to its ability to ^{release iodine from potassium iodide solutions at 0} ° C. This test will now be described.

test

A test solution is prepared by dissolving the following substances in 1000 ecm of distilled water:

Sodium pyrophosphate Na ₄ P ₂ O ₇ 10H ₂ O 2.5 g

Sodium perborate NaBO ₂ · H ₂ O ₂ · 3 H ₂ O 0.615 g

(with 10.4% available oxygen)

Sodium dodecylbenzenesulfonate 0.5 g

Such an amount of an amide is added to this solution at 60 ^° C. that one molecule of amide is introduced for each atom of available oxygen present. A water-soluble amide or one which is liquid at 6O ⁰ C or dispersed in the solution JerchT is, the test solution was added immediately. Other amides are dissolved in 10 ml of ethyl alcohol and then added to a test solution which is prepared using 990 ml of distilled water.

The mixture obtained by addition of the amide is stirred vigorously and maintained at 6O ⁰ C. 5 minutes after the addition, a portion of 100 ecm of the solution is drawn off and immediately pipetted into a mixture of 250 ecm of crushed ice and 15 ecm of glacial acetic acid. 0.4 g of potassium iodide is then added and the released iodine is immediately titrated with 0.1 N sodium thiosulphate solution with starch as an indicator until the blue color disappears for the first time.

An amide which, according to the invention, is used as an activator for hydrogen peroxide or a persalt in the Low temperature bleaching is suitable is one which in this test has a titer of there is at least 1.5 ecm of 0.1 n-sodium thiosulphate.

The invention thus provides a method for bleaching textiles with aqueous, organic Peroxide baths containing nitrogen compounds, which is characterized in that as an activating agent an organic nitrogen compound is used, which is added to 100 ml of an aqueous solution of 0.0615 g of sodium perborate (10.4% available oxygen) is added in an amount that per atom available oxygen 1 molecule of nitrogen compound is introduced after heating for 5 minutes to 60 ° C, addition of 250 ecm of crushed ice and 15 ecm of glacial acetic acid and 0.4 g of potassium iodide in the back titration of the released iodine with starch as an indicator, at least 1.5 ml of 0.1 N sodium thiosulphate solution has been consumed and that of the general formula

RCOs

R ₁ CO-

NO,

corresponds, in which R and R _{1 represent} an alkyl or phenyl radical containing 1 to 3 carbon atoms and R _{2 represent} an otherwise arbitrary organic radical corresponding to the above test method, whereby R ₁ and R _{2 are formed} via the —C ON compound an optionally substituted caprolactam, N'-acylated barbiton, phthalimide, anthranil, N'-acylated hydantoin or> saccharine ring can be combined.

The group RCO is preferably an aliphatic radical, in particular one with 2 to 4 carbon atoms, ζ. B. the acetyl radical. Furthermore, the radical RCO is preferably not bonded to any of the radicals R ₁ and R ₂ with the formation of a divalent radical.

An organic acetylamide is preferably used, in particular one in which the Nitrogen of the amino group is substituted by a second acetyl radical. Other useful compounds are the organic propionyl, butyryl and benzoyl amides. Lots of useful connections are found among the arylamides, in particular anilides, for example -JslyN-diacylanilme. Ν, Ν-Diacetylanjjjkrist particularly useful.

Examples of typical compounds are

Titer

Ν, Ν-diacetylaniline 6.05

Ν, Ν-diacetyl-p-toluidine 6.65

tyN-diacetyl-p-chloroaniline 5.85

N, N-dibutyrylaniline 5.2

Dibenzanilide, 3.1

N-acetyl caprolactam 4.5

Ν, Ν'-diacetylbarbitone 2.8

N-acetylphthalimide 4.35

N-acetyl saccharin 5.6

Other suitable amides are N-acetylanthranil and N, N'-diacetyl-5,5-dimethylhydantoin.

The amides in question are normally solid and in practice are finely mixed with the persalt

3 4

distributed form mixed to ensure that which the following substances are in parts by weight

if the bleach thus obtained is used, held, made:

it is easily dispersed in the 'bleach bath Since the sodium dodecylbenzenesulfonate 21.9

Amides in general show a tendency through the anhydrous alkaline sodium silicate 6,6

Persalts to be decomposed should be the mixtures ₅ tetrasodium pyrophosphate 13.1

pentasodium tripolyphosphate 21.9 prepared in practice only before use

will. · Sodium Sulphate Anhydrous 24.4

In the methods of the invention, the water-water 121

substance peroxide as such directly to the

can be added to the bleaching bath, but preference is given to 10 parts by weight of this base powder

wisely, it is made from an inorganic persalt in 0.865 parts of sodium perborate tetrahydrate with 10.4%

Freedom set. The inorga- available oxygen and 1.03 parts of N, N-diacytyl-

niche persalts are the usual ones, which are added to p-toluidine when dissolving.

give off hydrogen peroxide in water, and a 0.44 percent by weight aqueous solution of this suitable compounds are e.g. B. alkali perborates, 15 total agent, which is 0.37% of the base powder,

-percarbonates, -perpyrophosphates and -persilicates. 0.00335% available oxygen and 0.0382%

Such salts probably contain crystallization Ν, Ν-diacetyl-p-toluidine, which is 1.07 atoms

hydrogen peroxide and are therefore not a! s real addable oxygen for every molecule of amide,

To look at persalts. contained, was in a thermostat to 6O ⁰ C

Preferably, the bleaches contain the invention. A soiled with tea white tree extension from V4 to 4, in particular ^l / ₂ to 1.5 molecules woollens was immersed in the solution for 10 minutes of reactive amide availability for each atom and constantly stirred (the ratio of Waschflüssigbaren oxygen in the used persalt, and at speed to stuff was 20 parts to 1 part by weight), the bleaching process is then taken out of this ratio of amide, applied in warm distilled to available oxygen. 25 rinsed with water and finally dried and

In practice, the processes are ironed out according to the invention.

The increase achieved by the washing, in particular at a pH between 8 and 11, by the percent of the reflectance of the cloth was carried out with a hydrogen peroxide or persalt, the possibility of using a Hunter reflectometer using a bluetooth device of the low temperature bleach 30 filters. The increase in percent reflectance form effective means. Once this was 16.1. If something has been soiled in the same way, the bath can, if desired, also be made acidic in the same way with a solution of the stuff. Accordingly, the bleaching agent should be washed, except that no agent was preferably also used in sufficient amounts of the amide, the increase in common alkaline substances was observed to that 35 percent reflectance of only 10.9 pH conditions in use the means to create. which indicated that the amide a better bleaching-Suitable alkaline substances are alkali carbonates, capable of ^{causing at 60 0} C,
phosphates and silicates. The phosphates can. .
Phosphate or water-soluble condensed example
Phosphates, for example tripolyphosphates and pyro- 40 A cleaning and bleaching agent would be like in the phosphate. Example 1 prepared, except that Ν, Ν-diacetyl-p-chloro

Other common substances can be used in the case of bleaching aniline (1.14 parts) as an amide,
process and bleaches are used, and a 0.44 percent by weight aqueous solution of the particularly it is expedient to incorporate a total detergent, which contains 0.37% of the cleaning substance, so that the bleaching process is equal to 45 base powder, 0.00335% available oxygen and expires early with a washing process. Organic 0.423% N, N - diacetyl - ρ - chloroaniline, these are detergent substances that can be introduced into the bleach bath or 1.06 atoms of available oxygen for each molecule - are either contained in an amide, was used to be with Tea soaps or soap-free detergent substances, for example soiled white stuff in exactly the same way as an alkyl aryl sulfonate or an alkyl sulfate. To wash the 50 ways as described in Example 1. The cleaning and bleaching agents will in practice also contain common additives. B. Alkali Sulphates, increase of 17 in percent reflectance. alkaline substances, such as the sodium _ already mentioned. .
carboxymethyl cellulose and fluorescent brighteners. example
In general, a cleaning or bleaching agent will contain about 10 to 15 percent by weight of an organic game 1 to 10 parts by weight of the base powder of ancillary agent. holding 13% available oxygen, and 1.03 parts

Substances which, according to the process of the invention, are added to N, N-diacetyl-p-toluidine.

Can be bleached are those which can be bleached with a 0.43 weight percent aqueous solution of the

Persalts can be bleached, e.g. B. stained cotton fabrics 60 total agent, which is 0.37% of the base powder,

and other stained or dirty stuff and 0.0032% available oxygen and 0.038% Ν, Ν-di-

Fibers. . acetyl-p-toluidine was used to make a

The invention is further enhanced by the following cotton sheets heavily soiled with tea

Examples explained. Using the procedure of Example 1 to bleach.

η · · 1 1 ⁶ 5 An increase in the percentage reflectance of

^{a e l sp 1 e} '' 18.7 was observed compared to 13.2 when a

A cleaning and bleaching agent! was used under the same solution, but without the amide

Using a spray-dried base powder.

Example 1 4

• To 10 parts by weight of the base powder from example 1 were 0.665 parts of sodium percarbonate with 13% available oxygen and 1.14 parts of Ν, Ν-diacetyl-p-chloroaniline added.

A 0.43 weight percent aqueous solution of the total agent, which contains 0.37% of the base powder, 0.0032% available oxygen and 0.042% Ν, Ν-diacetyl-p-chloroaniline was used to bleach a cotton cloth heavily soiled with tea using the procedure of Example 1 was used. An increase in percent reflectance of 16.9 was found compared to 13.2 when the same solution but without the amide was applied became.

Example 5

An aqueous bleach solution was prepared using 0.032% by weight sodium perborate tetrahydrate with 10% available oxygen, 0.12% tetrasodium pyrophosphate, and 0.046% N, N _T dibutyrylaniline (liquid). A cotton cloth heavily soiled with tea was then washed with the solution using the procedure of Example 1. An increase in the percent reflectance of 14.5 was observed compared to 9.2 when an equal solution but without the amide but otherwise containing the same amounts of perborate and pyrophosphate was used.

Example 6

100 parts by weight of an aqueous solution containing 0.37 parts of the base powder of Example 1 and 0.023 parts of sodium percarbonate with 14% available oxygen were _{mixed with 0.046 parts of N 5} N-dibutyrylaniline. The resulting cleaning and permanent solution was used to bleach a cotton cloth heavily soiled with tea using the procedure of Example 1. An increase in percent reflectance of 17.2 was observed compared to 11.8 when the same solution but without the amide was used.

Example 7

45

A bleach was prepared by mixing 3.2 parts by weight of sodium perborate with 10% available oxygen, 12 parts tetrasodium pyrophosphate and 3.2 parts N-acetylcaprolactam. A Cotton towel heavily soiled with tea was made using the procedure of Example 1 with a 0.18% aqueous solution of the agent ^ = bleached. An increase in percent reflectance of 13.3 was observed compared to 9.2, if the same solution without the amide, but otherwise with the same proportions of perborate and Pyrophosphate was used.

Examples

A bleach was prepared and used exactly as in Example 7 except that 3.8 parts of N-acetylphthalimide were used was used as the amide and the solution contained 0.19% of the agent. The watched The increase in percent reflectance was 11.5.

Example 9

0.62 parts of sodium percarbonate were added to 10 parts by weight of the base powder from Example 1 14% available oxygen and 1.21 parts N-acetylsaccharin added.

A 0.44 percent by weight aqueous solution of the total agent, which contains 0.37% of the base powder, Containing 0.0032% available oxygen and 0.045% n-acetylsaccharin was strong for bleaching one using the procedure of Example 1, cotton cloth soiled with tea was used. The observed percentage increase in reflectance was 17.1 compared to 11.5 when the same Solution without amide was applied.

Claims (1)

Claim: Process for bleaching textiles with aqueous peroxide baths containing organic nitrogen compounds, characterized in that the activating agent used is an organic nitrogen compound which, to 100 ml of an aqueous solution of 0.0615 g of sodium perborate (10.4% available oxygen) in an amount added that 1 molecule of nitrogen compound is introduced per atom of available oxygen, after 5 minutes of heating to 6O ⁰ C, addition of 250 ecm of crushed ice and 15 ecm of glacial acetic acid and 0.4 g of potassium iodide in the back titration of the released iodine with starch as an indicator at least 1 , 5 ml of 0.1 N sodium thiosulphate solution consumed and that of the general formula RCO NO, RiCO ' corresponds yes which R and R ₁ containing alkyl or a phenyl-Uend R is a 1 to 3 C-atoms ₂ above a test method corresponding, otherwise any organic radical where R ₁ and R ₂ on the compound to form -CON an optionally substituted caprolactam, N'-acylated barbitone, phthalimide, anthranil, N'-acylated hydantoin or saccharine ring can be combined.