US2043069A

US2043069A - Preparation of dyed filaments and films

Info

Publication number: US2043069A
Application number: US755848A
Authority: US
Inventors: Rusch Roland; Schmidt Hermann
Original assignee: IG Farbenindustrie AG
Current assignee: IG Farbenindustrie AG
Priority date: 1933-12-06
Filing date: 1934-12-03
Publication date: 1936-06-02
Anticipated expiration: 1953-06-02

Description

Patented June 2, 1936 onrrso STATES PATENT OFFICE Roland Riisch, Opladen, Austria, and Hermann Schmidt, Leverkusen-Wiesdorf, Germany, assignors to I. G. Farbenindustric Alrtiengesellschaft, Frankfort-on-the-Main, Germany No Drawing. Application December 3, 1934,

Serial No. 755,848. 1933 3 Claims.

The present invention relates to the preparation of dyed filaments and films, preferably to the preparation of dyed cuprammonium and viscose silk.

Up to the present time the dyeing of artificial silk from regenerated cellulose was usually carried out in special dye-works and not in the artificial silk works, since the dyeing process on account of its complicated character and the variety of methods of carrying out the process requires a thorough acquaintance with the art of dyeing which the experts of the artificial silk industry generally do not possess. It is, there'- fore, a problem to combine the spinning and dyeing of artificial silk in a simple manner so as to enable the manufacturers of artificial silk to prepare dyed material without the necessity of using complicated dyeing methods. It has been tried to solve this problem by incorporating dyestufis within the spinning solution, the working up of the latter, 1. e. precipitation, washing, rinsing, bleaching, etc. being performed in the usual manner. However, this process shows the disadvantage of yielding dull shades, the yield of the dyestuff employed being relatively small.

It is the object of our present invention to avoid this disadvantage without influencing the spinning process itself. We have found that filaments and films prepared from artificial masses, such as regenerated cellulose, cellulose esters and others can be dyed excellently vivid and uniform shades by incorporating within the spinning solutions serving as starting material for the preparation of the filaments and films a vat dyestuff and subjecting the same after the preparation of the filaments and films has been completed to a reduction process so as to form the leuco compound and to a subsequent oxidation process so as to regenerate the dyestuff. Our new process is intended to be employed in the first line for the preparation of artificial threads from regenerated cellulose such as for the preparation of cuprammonium or viscose silk. In this case that vat dyestufi is suspended in the spinning solution, from which the artificial threads are prepared by projecting the same into the precipitating baths, the threads being then subjected to an after treatment with a reducing agent, which is capable of vatting the dyestuff and to a subsequent treatment with an oxidizing agent, such as oxygen or air.

As reducing bath there is used in the first line an alkaline hydrosulfite bath, it being understood that other reducing agents known to be In Germany December 6,

capable of vatting vat dyestuffs, being likewise operative in our present process. The aftertreatment of the threads with reducing and. oxidizing agents is preferably effected after the preparation of the filaments or films has been performed. Obviously, this means that the vatting and oxidizing of the vat dyestuffs can be performed at any stage of the finishing operations as soon as the thread has acquired sufiicient strength to withstand the strain involved by the reducing and oxidizing process, and we wish it to be understood that all these possibilities are intended to be embraced by the term after the preparation of the filaments and films has been performed used in the claims.

As a matter of fact the manner of precipitating the filaments and films and of effecting the finishing operations is not materially changed when working according to our new process, Washing, rinsing, bleaching, sizing and weighting being performed in the usual manner. Furthermore, we wish to point out that our inven tion is in no way restricted to a special spinning and precipitating process, it being to be understood that it is operative in the dry-spinning and stretch-spinning process and regardless as to the nature of the precipitating bath employed.

The effect involved by our present invention lies in the fact that shades of a much better brilliancy and a much better yield of the dyestuff are obtained than it is possible when working as described in the preamble i. e. by merely suspending the dyestuffs in form of pigments in the spinning solutions. Our experiments have proved that this is more or less true in the case of every vat dyestuff and our invention is in no way restricted to special dyestufis or a special class of vat dyestuffs.

The following examples will illustrate the invention, without restricting it thereto:

EXAMPLE 1 cuprammonium silk To a 10% cuprammonium cellulose solution there are added (calculated on the weight of the cellulose) of Indanthrene blue GDC double paste (Colour Index No. 1113), after pasting the latter with water. The precipitation of the threads is performed in the usual manner by projection through a nozzle into an acid precipitating bath. After removal of the copper, the material is treated at 5060 C. for half an hour in an aqueous bath containing per litre 12 cos. of an aqueous solution of sodium hydroxide of 40 B. and 2-3 grams of powdered sodium hydrosulfite. The material is then washed, oxidized, treated with a soap solution, dried and finished as usual. It is of advantage to add some sodium chloride to the alkaline hydrosulfite bath. The yield and brilliancy of the shades obtained in this manner is by far better than that of the shades obtained by mere adding the dyestuif without subsequent application of reducing or oxidizing agents.

Instead of the Indanthrene blue GDC, there can be used with the same advantage, for instance, the following dyestuffs:

Indanthrene brilliant green B (see Colour Index Suppl. p. 43)

Indanthrene red brown 5RF (see Colour Index Suppl. p. 43)

Indanthrene black BGA (see Colour Index No. 1102) Indanthrene dark blue BOA (see Colour Index No. 1099);

Indanthrene yellow 3RN (see Colour Index page 355) Indanthrene yellow 3GP (see Colour Index Suppl. p. 43);

Indanthrene green GG (see Colour Index page 43).

EXAMPLE 2 Viscose silk To a 7% cellulose xanthate solution there are added 5% (calculated on the weight of the cellulose) of Indanthrene brilliant green B paste fine (see Colour Index Suppl. p. 43). The solution is then spun with the known acid baths. The threads are washed with a weak aqueous solution of sodium carbonate and then treated at 50-60 C. for half an hour in an aqueous bath containing per litre 12 cos. of an aqueous solution of sodium hydroxide of 40 B. and 23 grams of sodium hydrosulfite, in order to reduce the dyestuif of the leuco compound. The material is then washed, oxidized and finished in the usual manner. The yield and brilliancy of the shades obtained in this manner is by far better than that of the shades obtained by mere adding the dyestuff without subsequent application of reducing and oxidizing agents.

EXAMPLE 3 Cuprammonium silk To a cuprammonium cellulose solution of the usual composition there is added a mixture of the following dyestuffs, the mixture being intensely mixed in a suitable apparatus, for instance, a ball mill:-

5% of a dibenzanthrone paste,

7.2% of a brown dyestufi paste (obtainable, for instance in accordance with U. S. P. 1,690,236 [dicarbazole of IA-trianthrimidel),

6% of a yellow pasted dyesuif, obtainable, for instance, by reacting with sulfuric acid monohydrate upon 1.5-trianthrimide,

the quantities of the dyestuffs being calculated on the weight of cellulose employed. Preferably, the dyestuffs are used in a finely dispersed form. The spinning solution thus obtained is spun into a Weakly alkaline precipitation bath. The copper is removed from the threads by means of a 10% aqueous solution of sulfuric acid. The material is then thoroughly washed out and treated at 4050 C. for one hour in an aqueous bath containing per litre 5 cos. of an aqueous solution of sodium hydroxide of 40 B., 2 grams of sodium hydrosulfite and 20 grams of crystallized sodium sulfate. After rapidly rinsing in water several times, a completely homogeneous dark-brown shade is obtained.

We wish to point out that the dyestufi combination employed in this example would not be applicable in the usual dyeing of ready threads, films, ribbons or the like, as it would yield unequal fancy shades.

EXAMPLE 4 Viscose film To a 7% cellulose xanthate solution there are added 5% (calculated on the weight of the cellulose) of Indanthrene brilliant green B fine paste. The viscose solution is projected through a nozzle of about 1 metre breadth into the known acid precipitation baths, whereby the cellulose is regenerated in form of a broad film. The film is Washed with the usual acid and alkaline precipitating baths and, after removal of the impurities, treated at 50-60 C. for half an hour in an aqueous bath containing per litre 12 cos. of

an aqueous solution of sodium hydroxide of 40 B. and 2-3 grams of sodium hydrosulfite. The film is then washed again, oxidized, washed once more and dried on drying rollers as usual. An intensely colored film is obtained.

We claim:

1. In the process of preparing dyed filaments and films from artificial masses such as regenerated cellulose, cellulose esters and ethers, the modification which comprises incorporating within the solution serving as starting material for the preparation of the filaments and films a vat dyestuif and subjecting the same after the preparation of the filaments and films has beenperformed to a reduction process so as to form the leuco compound and to a subsequent oxidation process so as to regenerate the dyestuff.

2. In the process of preparing dyed threads from regenerated cellulose the modification which comprises incorporating within the solution serving as starting material for the preparation of the threads a vat dyestuif and subjecting the same after the preparation of the threads has been performed to a reduction process so as to form the leuco compound and to a subsequent oxidation process so as to regenerate the dyestuff.

3. In the process of preparing cuprammonium silk threads from regenerated cellulose, the modification which comprises incorporating within the solution serving as starting material for the preparation of the threads a vat dyestufi and subjecting the same after the preparation of the threads has been performed to a reduction process so as to form the leuco compound and to a subsequent oxidation process so as to regenerate the dyestufi.

ROLAND RiiscH. HERMANN SCHMHDT.