DE247637C - - Google Patents

Description

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K PATENT OFFICE.

PATENT LETTERING

- M 247637 CLASS Bl GROUP L

Process for bleaching textile fibers. Patented in the German Empire on March 27, 1910.

the priority

The wool used to make fabrics is first given a thorough one Subjected to degreasing with soda and soap; for many purposes, however, what is achieved in this way is sufficient Don't know yet and you are forced to destroy the yellow-gray color of the wool. Most of the time one is content to raise the white by sulphurizing, i. H. the reducing Utilize the effect of the sulphurous acid; sometimes the oxidizing one is also used 'Effect of hydrogen peroxide on the dyes still contained in the wool.

This latter method is expensive and is therefore only used for exceptional needs used; the sulphurous acid, on the other hand, gives a less durable white than the one treated in this way Wool takes on its yellow color again when treated with hot alkaline Solutions (Walke) comes into contact or is simply wetted with an alkaline solution.

It has now been observed that the free stearic acid, with wool or similar textile fibers, which have already been degreased, brought into contact under suitable conditions, possesses the surprising property, the same bleaching very quickly, and that, apart from the cheap cost price of the process, the fiber treated in this way is a durable one White shows that after drying it can withstand all treatments that come into consideration during further processing.

This hitherto unknown property of stearic acid was all the less predictable, as this product a common component of degreasing or emulsifying agents Forms mixtures without any significant effect on the color of the fiber being observed would have been. This is probably due to the fact that this requires special conditions which can be characterized as follows:

1. The stearic acid must be as complete as possible to be emulsified.

2. The emulsion to be used must still have an acidic character. at The bleaching effect is far less in the presence of alkalis.

The first of these conditions is easy to meet, namely by means of emulsifying Bodies such as soaps, vegetable mucilages, panama wood extract, etc., such as those in the process of French patent 400792 used to make fats to emulsify.

As for the second condition, namely the acidic character of the emulsion, so it is very important as most emulsifiers are more or less alkaline Have character and the alkalinity is known to favor the yellowing of wool and thus partially thwart the intended purpose.

The present method of bleaching, for example wool, is very cheap, like prove the quantities used in the example given below; this low The cost price of the bleaching process is significantly reduced by the fact that one the bleach bath after a certain time by simply boiling with the sufficient A lot of soda can turn into a good soapy water, with the formation of stearin soap solution, which is used for the initial degreasing of the raw material.

The following example should serve to precisely characterize the process.

Example.

30 parts of stearic acid are melted in 100 parts of a concentrated panama wood extract solution or similar acting Quillaya species; achieved by vigorous stirring of the mixture you get a liquid paste of good shelf life. You can also add a small amount of neutral soap to the panama wood decoction - 2 to 5 parts - add to increase the shelf life or change the desired one Consistency.

To bleach wool with this emulsion, to order a 30 to 60 ^above warm bath containing from 1 to 3 parts of the above emulsion to 100 parts of water, spread it with ease. The goods are handled in the milky liquid for 5 to 10 minutes, then removed, squeezed or spun to recover the excess bath, rinsed well and finally dried. The slower the drying takes place, the gentler the white will be.

The goods bleached in this way remain white during later processing, even in the present of alkalis. The white also increases during storage.

The bleach bath can also be used cold if the duration of the action is extended, the end result remains the same.

The objection that the bleaching effect is deposited on the surface of the fiber Stearic acid can be recycled is not conclusive, because on the one hand it is through vigorous rinsing practically completely removes the excess stearic acid emulsion, and on the other hand the whiteness of the wool so bleached is not changed if it is is treated with organic solvents which are able to dissolve stearic acid, like ether, gasoline, etc.

Claims (1)

Patent claim: Process for bleaching textile fibers, consisting in that as a bleaching agent an emulsion containing free stearic acid in excess is used.