US2044885A

US2044885A - Spinning artificial silk

Info

Publication number: US2044885A
Application number: US518598A
Authority: US
Inventors: Kleine Johannes; Pfannenstiel Hugo; Matthaes Werner
Original assignee: IG Farbenindustrie AG
Current assignee: IG Farbenindustrie AG
Priority date: 1930-03-06
Filing date: 1931-02-26
Publication date: 1936-06-23
Anticipated expiration: 1953-06-23
Also published as: NL33975C; GB361760A; FR712411A; NL55651C

Description

Patented June 23, 1936 UNITED STATES PATENT OFFICE SPINNING ARTIFICIAL SILK No Drawing. Application February 26, 1931, Serial No. 518,598. In Germany March 6,

Our present invention relates to a new process of manufacturing artificial fibers from a viscose solution and more particularly to a new setting bath used in the manufacture of artificial products from viscose.

Viscose silk of high tenacity has already been made by spinning viscose into precipitating baths containing at least 45% of sulfuric acid monohydrate'.

According to this invention it is possible to obtain threads having a strength of over 200 grams per 100 deniers by making use of such precipitating baths as contain considerably smaller amounts of sulfuric acid monohydrate. The proposed aim may be reached by spinning viscose, produced from unripened or only slightly ripened alkali cellulose, into baths containing besides 10 to 30% of sulfuric acid monohydrate more than 30% of a bisulfate, and stretching the threads during their process of manufacture. It is advantageous to almost saturate the acid solutions with bisulfate. The best action is obtained with ammonium bisulfate which dissolves particularly well in acid baths. Sodium bisulfate and other easily soluble bisulfates or mixtures of different bisulfates may, however, likewise be used. Under the term slightly ripened alkali cellulose we wish to be understood alkali cellulose which has ripened for a shorter time than that considered to be normal, that is to say less than 96 hours at a temperature of 18 C.

It is a known fact that baths which contain a bisulfate besides free sulfuric acid, do not give satisfactory results (cf. German Patent No. 287,-

955, page 1, lines 33-37) Hence it is surprising that baths of the said composition not only allow of well spinning, but even yield a silk of a particularly high strength, if the baths-contain besides sulfuric acid considerable quantities of bisulfate and if the thread is stretched while being spun. The threads may be stretched either by stationary rods or by eyes or by other mechanical means, or they may be stretched by enhancing the speed of spinning or by the current of the spinning bath or by a prolonged passage through the bath.

Although viscoses from alkali cellulose ripened for several days still yield strengths of up to 2 grams per denier, especially when they have a higher content of cellulose, viscoses from unripened alkali cellulose will always give higher strengths. stretched when particularly highly sulfided xanthogenates are used. It is advantageous to prevent any degradation of the cellulose during The thread can more easily be,

13 Claims. (CI. 1854) the diiferent steps of manufacture; this may, for instance, be done by completely excluding oxygen or by similar measures. Threads from cellulose which has been degraded to as small an extent as possible have, as a rule, higher strengths or in the w. An unripened alkali cellulose, sulfided with 32 per cent by weight of carbon disulfide (calculated upon cellulose) is dissolved to form a viscose containing 6% of cellulose and 6.5% of alkali.

b. A viscose is made according to a but the alkali cellulose is sulfided with per cent by weight of carbon disulfide.

The viscose prepared according to a or b is spun into a precipitating bath containing 28 per cent of. free sulfuric acid and being nearly sat urated with ammonium bisulfate and sodium bisulfate, through a spinning nozzle provided with 700 perforations, the width of each perforation being 0.1 mm. The viscose pump is thus adjusted to deliver about 9 com. of the viscose solution per minute. The length of passage of the threads in the bath may be 25 cm., while the length of passage in the air may be cm. The speed of draught is 30 in. per minute. Under these con ditions, a thread is obtainable having a total titer of deniers. The spinning temperature of the bath is 40 C. After leaving the precipitating bath, the thread is stretched over 3 eyes spaced apart in the form of a triangle.

The strength of the threads obtained exceeds 350 grams per 100 deniers with an elongation of 6 to '7 per cent.

Example 2 In a xanthogenate machine, cellulose ls introduced into a caustic soda solution of 19% strength. After the swelling of the cellulose, the mass is kneaded at 10 C. until it has become homogeneous. The mass is sulfided with 50% of carbon disulfide for 3 to 4 hours at'a temperature of 26 C.; the sulfided product is dissolved at 15 C. in a caustic soda solution of 1% strength to form a viscose containing 5% of cellulose and 4% of alkali.

The viscose is spun into a bath consisting of 28% of free sulfuric acid, 32% of ammonium bisulfate, 8% of sodium bisulfate and 32% of water while strongly stretching the freshly precipitated threads. During spinning the following working conditions are to be maintained:

The temperature of the bath is 37 C. The spinning nozzle has 120 perforations, the width of each perforation being 0.09 mm. The speed of draught is 30 m. per minute. The length of passage of the thread in the bath is 50 cm. and that through the air, likewise, 50 cm. The viscose pump is thus adjusted to deliver 7.2 ccm. of the spinning solution per minute.

The threads obtained have a total titer of 120 deniers, a strength of over 300 grams per 100 deniers and an elongation of 7 to 8%.

E :rample 3 There is spun a viscose from alkali cellulose which has ripened for a short time, for instance, for 12 hours, containing 9% of cellulose and 8% of alkali and having a viscosity of about 150 seconds determined in the ball viscosimeter (that is to say, a steel ball of 0.1 gram needs 150 seconds to pass through a tube of 18 mm. width and 20 cm. length filled with the viscose to be determined). The spinning bath consists of 24% of sulfuric acid, 35% of ammonium bisulfate, 12% of sodium bisulfate and 29% of water. The spinning temperature is 40 C. A spinning nozzle is used having 120' perforations, each perforation having a diameter of 0.09 mm. The length of passage of the thread in the setting bath is 25 cm. and that through the air 50 cm. The viscose pump delivers about 4 cm, per minute. After leaving the bath, the threads are stretched in the usual manner. They have a total titer of 120 deniers, a strength of 330, and an elongation of 6 to 7%.

Example 4 The spinning bath consists of a solution of 39% of ammonium bisulfate, 11% of sodium bisulfate, 18 per cent of sulfuric acid monohydrate and 32 per cent of water. Into this bath a viscose according to Example 1 a is spun at 40 C., through a spinning nozzle provided with 120 perforations, each perforation having a diameter of 0.07 mm. while stretching the freshly precipitated threads. The speed of draught is 30 m. per minute, the length of passage through the bath is 25 cm. and that through the air cm. The viscose pump is thus adjusted to deliver 6 com. of the spinning solution per minute.

The threads obtained have a total titer of 120 deniers, a strength of over 250 per deniers and an elongation of 6 to 7%.

.Escample 5 A viscose according to Example 1 a is spun at 45 C. under the same conditions as mentioned in the foregoing example, into a precipitating bath consisting of 12% of sulfuric acid monohydrate, 48% of ammonium bisulfate, 14% of sodium bisulfate and 26% of water, while strongly stretching.

The threads obtained have a strength of 230 per 100 deniers and an elongation of 8.3%.

Our invention is not limited to the foregoing examples or to the specific details given therein.

The passages through the bath and through the air may be varied in certain limits. The first named may be, for instance, 10 to 50 cm. or even longer and the latter may vary between 50 and 200 cm. As spinning nozzles there may be used, for instance, nozzles /0.05 (120 perforations of an individual diameter of 0.05 mm.) or nozzles 120/0.09, TOO/0.10 or 1000/0.10. The viscose pump may be adjusted with each spinning nozzle to deliver the quantity of spinning solution required for the desired total titer.

The same holds true with respect to the correct composition of the setting bath or to the temperature of the latter. Preferably a temperature between 30 to 50 C. is to be maintained during the spinning operation. However, this temperature likewise may be varied.

Viscose solutions having a higher or smaller content of cellulose than those indicated in the examples, may be used.

If necessary, a few simple comparative experiments should be made in order to determine the best working conditions, the most suitable composition and the best temperature of the setting bath to be used with a particular viscose solution prepared from an unripened or slightly ripened alkali cellulose.

As indicated above, other assistants well known in the manufacture of artificial silk, may be added either to the spinning solution or to the precipitating bath.

The processes of after-treating the fibers, such as washing, desulfurizing, bleaching and so on, are carried out as usual. In consideration of the acid and salt concentration adhering to the spun fiber we prefer, however, to join the washing immediately to the spinning operation.

All the various modifications mentioned above and changes in detail are considered to be within the spirit of our invention and the scope of the following claims.

What we claim is:

l. The process of manufacturing artificial fibers of high tenacity, which comprises causing a viscose prepared from an unripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 10 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of a bisulfate soluble in the acid bath, and stretching the freshly precipitated threads.

2. The process of manufacturing artificial fibers of high tenacity, which comprises causing a viscose prepared from an unripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 10 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate, and stretching the freshly precipitated threads.

3. The process of manufacturing artificial fibers of high tenacity, which comprises causing a viscose prepared from an unripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 10 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate and in addition an alkali metal bisulfate, and stretching the freshly precipitated threads.

4. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from an unripened alkali cellulose to pass through suitably formed openings into a coagulation bath containing 24 to 30 per cent of sulfuric acid monohydrate and at least ing the freshly precipitated threads.

5. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from an unripened alkali cellulose to pass through suitably formed openings into a coagulation bath containing 24 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate and in addition an alkali metal bisulfate, and stretching the freshly precipitated threads.

6. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from slightly ripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of a bisulfate soluble in the acid bath, and stretching the freshly precipitated threads.

7. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from slightly ripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 10 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate, and stretching the freshly precipitated threads.

8. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from slightly ripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 10 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate and in addition an alkali metal bisulfate, and stretching the freshly precipitated threads.

9. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from slightly ripened alkali cellulose to pass through suitably formed openings into a coagulation bath containing 24 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate, and stretching the freshly precipitated threads.

10. The process of manufacturing artifical fibers of high tenacity which comprises causing a viscose prepared from slightly ripened alkali cellulose to pass through suitably formed openings into a coagulation bath containing 24 to 30 per cent of sulfuric acid monohydrate and at least 30 per cent of ammonium bisulfate and in addition an alkali metal bisulfate, and stretching the freshly precipitated threads.

11. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from unripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 28% of free sulfuric acid and being nearly saturated with ammonium bisulfate and sodium bisulfate, and stretching the freshly precipitated threads.

12. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from alkali cellulose which has ripened for twelve hours to pass through suitably formed openings into a coagulating bath containing 24% of sulfuric acid, 35% of ammonium bisulfate, 12% of sodium bisulfate and 29% of water, and stretching the freshly precipitated threads.

13. The process of manufacturing artificial fibers of high tenacity which comprises causing a viscose prepared from unripened alkali cellulose to pass through suitably formed openings into a coagulating bath containing 12% of sulfuric acid, 48% of ammonium bisulfate, 14% of sodium bisulfate and 26% of water, and stretching the freshly precipitated threads.

JOHANNES KLEINE. HUGO PFANNENSTIEL. WERNER MAII'I'HAES.