US2326174A - Method and apparatus for the production of curled threads from cellulose acetate - Google Patents

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Aug. 10, 19439 G. RUTISHAUSER ,1

METHOD AND APPARATUS FOR THE PRODUCTION OF CURLED THREADS FROM CELLULOSE ACETATE Filed July 12, 1940 l l I 'l i i. 2 2 i 2 l Jmrenlor:

I Rufisbauser Patented Aug. 10, 1943. 2,326,174

METHOD AND APPARATUS FOR THE PRO- DUCTION F CURLED THREADS FROM CELLULOSE ACETATE Georg RutishausenBasel, Switzerland; vested in the Alien Property Custodian Application July 12, 1940, Serial No. 345,220 In Germany April 22, 1939 3 Claims.

The invention relates to a method and an apparatus for the production of curled threads from cellulose acetate.

It is known to utilise the thermoplastic properties of a structure from cellulose acetate or esters which may still contain swellingor soitening-media,'in order to impart to these structures a certain shape. In utilising this property and by means of fluted rolls an undulating, es-

regular and permanently lasting curling in that by adjusting the spinning conditions a small portion of its volatile solvent is left in the thread bundle coming out of the spinning shaft, this thread bundle being then sprinkled at once with water, preferably hot water, by means of a moistening device and finally conducted through one or several pairs of heated fluted rolls. The thread bundle thus curled is then cut to the depecially a curling, can be produced on an acesired staple length immediately and continually. tate-artificial silk thread. .If necessary, a re-drying can take place fol- However, different difiiculties occur in such lowing on the cutting or later, but this has nothcurling methods. If for curling a normal, ready ing to do with the curling to be obtained. spun, dry thread is employed, the curling is not In this simple manner it is possible, to obtain lasting, or only when high temperatures and on a moving thread bundle of acetate artificial pressures are employed which cause damaging silk a permanent and lasting, very regular curl of the thread treated in this manner. If a ing. Sticking or winding of the fibres on the thread, which contains a swelling or softening rolls does not take place. By selection of the medium already added to the spinning mass, is fluted rolls the fibres can be set as regards IlllIll treated in a similar manner, difiiculties of variher of curlings per unit of length and shape of ous kinds also result. For instance it easily hapthe curling arcs (round, flat, acute arcs). If the pens that the threads are stuck the one on the bundles of thread are conducted between two other or on the fluted rolls, so that it is imsuccessive pairs of rolls, the axial planes of possible to continually carry out the method, which are inclined at an angle the one to the or these swelling and softening media must be other, or if the thread bundles are turned after removed again after the curling, as otherwise the first curling and prior to the introduction inthe curling does not last and a thread containto the second, parallel pair of rolls, it is possible ing these media shows a much too strong elasto produce, according to the invention, a curlticity and results in an unelastic, unsuitable ing after the manner of a double curve. product, If however the swelling and soften- The curling thus obtained is even more like ing media are subsequently applied only exterthe natural wool curling, very lasting and does nally on to the ready spun thread, such as celnot disappear by carding or combing in the malulose acetate, swelling aqueous salt solutions, or chine for further treatment. The curled fibres mixtures of organic liquids such as, for instance, further can be subjected repeatedly to a longia mixture of a dissolving or swelling medium tudinal stressing'or moistened and dried, colored for cellulose acetate together with a non-disor otherwise treated without causing the curling solver or filling medium, a treatment of longer to disappear. The curling is permanent and duration preceding the curling is necessary with lasting. these media and must be very accurately regu- The method presents the advantage that it latecl or supervised. This is not simple and re- 40 can be applied on to the moving thread bundle, quires additiona1 time, arrangement and auxilispace being saved' owing to the simplicity and ary substances. After the curling a re-treatsmall size of the treating elements, this having ment has to take place to liberate the threads .an especially favourable efiect if the method is from these media. applied to the rapidly running thread bundle. If in such methods higher spinning speeds are The threads coming from the spinning shaft. applied such as usual for instance in the dryare moistened, curled and cut in a continuous spinning method, the above mentioned methods operation, so that the curled acetate cellulose fail as the time during which the swelling media wool is obtained quite ready, this being especially act is too short to enable a suificient action of valuable for production in large quantities. the running thread. A finished product insuffi- The manufacturing process of the ready celciently curled would then be obtained or prelimlulose wool requires a very short time, only about inary and subsequent treating devices would two seconds being necessary for the spinning, have to be employed. curling and cutting. Owing to these high speeds The invention avoids in a very manner a machine unit with 100 spinning points turns j these inconveniences and admits of obtaining a out per day at least 1000 kg. The several machine elements work so'securely and reliably, that practically no one is required for attendance except for the pressing of the ready bales. .The cellulose wools produced according to the new method have an extraordinarily uniform and lasting curling, the curving and the number of curlings being as desired.

The method can be carried out at any spinning speeds usual in the dry-spinning process. For instance a bundle of fibres of 500 to 1000 titre at 3% tit-re per single fibre is spun in any spinning shaft at a speed of at least 150 m. per minute. The drying process in the cell is adjusted so that the delivered thread contains 4 to 10, preferably 6% solvent. In front of the curling r011 one or several bundles of fibre of the above titre are moistened with water, preferably hot water, so that they show a Water content from 6 to 18, preferably 14%. The fibres then mois-' tened with volatile solvent and water are fed to a pair of. curling rolls heated to 80 C. to 180 (3., preferably 130 0., this pair of curling rolls rotating at a speed of about in. per

minute. The curling which is produced shows 6 to '7 arcs per cm. The cutting machine following on the curling rolls draws the curled bundle ofi the curling roll in slightly stretching it and cuts the threads in staples of for instance about mm. length.

The accompanying drawing shows by way of example an apparatus for carrying out the method according to the invention.

In this drawing 2 designates the spinning shafts or the drying chambers of the same, 3 the moistening roll, 4 a pair of fluted rolls, 5 another pair of fluted rolls, the axis of the latter pair of rolls being perpendicular to that of the curlin rolls 4. 6 designates the cutting machine and I the pile of cut curled wool.

Iclaim:

1. Method for the production of curled threads spun by the dry spinning process from cellulose acetate, which comprises moistening with water in a proportion of from 6% to 18% freshly spun threads still retaining from the spinning process from 4% to 10% of solvent, and then feeding the threads to curling rolls.

2. Method for the production of curled threads spun by the dry spinning process from cellulose acetate, which comprises moistening with water in a proportion of from 6% to 18% freshly spun threads still retaining from the spinning process from 4% to 10% of solvent, then feeding the threads to curlingrolls, and cutting the curled threads to form a Wool-like material.

3. Method for the production of curled threads according to claim 1 in which the rolls are heated to approximately C.

GEORG RUTISHAUSER.

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