US1949983A

US1949983A - Spinning of artificial filaments and the like

Info

Publication number: US1949983A
Application number: US484788A
Authority: US
Inventors: Taylor William Ivan
Original assignee: Celanese Corp
Current assignee: Celanese Corp
Priority date: 1929-11-25
Filing date: 1930-09-27
Publication date: 1934-03-06
Anticipated expiration: 1951-03-06
Also published as: GB343936A; FR702509A

Description

March 6, 1934. w. I. TAYLOR 1,949,983

SPINNING OF ARTIFICIAL FILAMENTS AND THE LIKE Filed Sept. 27, 1930 ooooboo\ooooo WJLUAM I. TAYLOR WVE'NTUR ATTUHNEYS Patented liter. 19334 UN' i-i PATENT OFFICE SPINNING OF ARTIFICIAL FILAMENTS AND THE LIKE Application September 27, 1930, Serial No. 484,788 In Great Britain November 25, 1929 11 Claims.

This invention relates to the production of filaments, ribbons, straws, and the like from solutions of cellulose derivatives, for example, cellulose acetate, and is an improvement in or modification of the invention described in U. S. application S. No. 375150 filed 1st July, 1929.

According to the above specification, the setting or solidification of the filaments, threads, or the like (hereafter referred to as threads) is eijiented by evaporating the solvent liquid from the extruded threads by means of a vacuum, or reduced or sub-atmospheric pressure. The evaporation may be accelerated by heat, or by the use of a current or" air, or other evaporative me- Hi dium, or by using both these agencies in conjunction with the application of a vacuum or reduced pressure. In carrying out such process a solution or" the cellulose acetate or other cellulose derivative in a volatile solvent mixture is exf truded through jets or spinnerets into a closed chamber or cell which is evacuated by means of a rotary or reciprocating air pump, a jet pump,

or an ejector or other appropriate apparatus for producing a vacuum, or sub-atmospheric pressure.

The threads, after they are hardened by evaporation, are led to a winding, or winding and twisting apparatus, outside the cell, being led from the cell through an opening in the cell wall,

' which opening may comprise a pin-hole which is kept of small dimensions to reduce to a minimum the amount of air entering the cell through the hole by reason of the degree or" vacuum existing Within the cell.

The present invention is concerned with methods of spinning under a vacuum or reduced pressure employing the form of apparatus just mentioned, one object to provide means whereby the thread of filaments may be drawn from the spinning cell without allowing any appreciable influx of atmospheric air, and especially moist air, into the cell through the opening by which the thread leaves the cell.

A dry spinning apparatus according to one feature of the invention comprises a spinning cell, a spinning jet in the cell, means for producing a vacuum or a sub-atmospheric pressure in the cell, an opening for withdrawing filaments from the cell and means by which the size of the opening may be adjusted to a small aperture whose size does not substantially exceed the cross-section of the thread. The opening in the spinning cell is of a size enabling the thread proceeding from the jet to be readily brought to the exterior of the cell for leading to a collecting device, and the size of the opening can then be reduced, e. g. by means of a sliding or pivoted plate, until there is just sufiicient space for the thread to pass without danger of the filaments being rubbed or torn.

According to a further feature of the invention, means may be provided by which the region of the aperture through which the thread passes may be supplied with dried air, so that moisturebearing atmospheric air is prevented from entering the cell through the aperture. This object may be achieved by causing a jet or jets of dry air to impinge on the wall of the cell round the aperture, or by flooding the region of the aperture with dry air. For the purpose of keeping the dry air in the region of the aperture and to reduce the amount of air to be supplied, a hood or cowl may be arranged round the aperture.

A form of apparatus according to the invention will now be described in greater detail with reference to the accompanying drawing, but it is to be understood that this description is given by Way of example only and is in no respect limitative.

Fig. 1 is a sectional side elevation of a vacuum spinning cell fitted with the means according to the invention;

Figs. 2 and 3 are a front elevation and a plan, partly in section, of the thread removing means according to the invention, as applied to a cylindrical spinning cell;

Figs. l, 5 and 6 show different forms of thread opening according to the invention.

Referring to Fig. 1, the dry spinning apparatus shown therein comprises a cell 11 fitted with a spinning solution supply pipe 12, a filter 13 and a spinning jet 14, from which are extruded a number of filaments 15. A door 16 in the rear wall of the cell renders the jet is accessible. A vacuum is maintained in the cell, the solvent vapours and other gases being carried oii by means of the pipe 1'? to a solvent recovery plant ties, by the pipe 18. The vacuum is initially obtained by exhausting the cell through the pipe 19, and is maintained by suction through the pipe 1'7, a vacuum gauge 20 being provided to indicate the degree of vacuum in the cell. Heating pipes 21 to maintain the required temperature in the cell may also be provided.

The details of the opening by which the thread is removed are clearly shown in Figs. 2 and 3 with reference to a cylindrical cell.

The front wall or" the cell is cut away to form a circular opening 22 of suificient size, say, of 2" diameter to allow the thread 15 extruded from the jet 14 in the cell to be seized and drawn to the outside of the cell, and about an axis 23 at one side of the opening 22 is pivoted a plate 24 whose lower edge is shaped to form a notch 25 with a rounded apex, which, when the plate is in position, just clears the lower edge of the opening 22 as shown in Fig. l. Alternatively, as shown in Fig. 5, the notch may be formed in the edge of the opening 22 and almost closed by the plate 24, or, and preferably, as shown in Fig. 6, both opening 22 and plate 24 may be notched, so that the two notches form a substantially circular opening when the plate is in position.

The aperture 26 which is left when the larger opening 22 is closed is preferably about l/64= inch in width or diameter, so leaving only a slight clearance when the thread 15 is passing from the inside to the outside of the cell 11. The edges of the aperture 26 should be smooth and rounded to avoid rubbing of the filaments. The filaments 15 are led out of the cell by the aperture, round a feed roller 28 and on to the cap spinning device 29 by which they are collected as twisted thread.

A slot 30 on the side of the plate opposed to the pivot 23 engages a stud 31 on the wall of the cell 11 when the plate 24 is closed, and this stud and the pivoting stud of the plate are provided with wing nuts 32, by means of which the plate 24 is held in place while being readily removable. The plate is packed on its inner surface with rubber or other suitable packing 33, and forms an airtight joint with the casing. An abutment may if desired be provided to ensure that the plate always assumes a definite position in which the small aperture has the correct dimensions and, if necessary, this abutment be adjustable, as by the provision of a micrometer screw, to regulate the size of the opening and compensate for any wear at the pivot of the plate.

Arranged around the opening in the cell wall is a metal hood 40, either of sufiicient size to allow the plate 24 to be opened inside it or provided with a slot ll to enable the plate to be swung clear of the opening 22. A pipe or jet 42 attached to the hood by means of nuts 43 connected by means of a pipe 44 to a suitable supply of dry air is arranged to -direct air to the inside of the hood 40, and preferably towards or on to the small aperture 26 from which the thread 15 emerges. A valve is preferably arranged to cut ofi the supply of air while the thread is first being drawn through the aperture, but this valve is not shown in the drawing. When the plate is turned into position, so that the required sub-atmospheric pressure can be maintained in the cell, the valve is opened and the ingress of moist air to the cell is effectively prevented by the jet of warm dry air with which the hood 40 is flooded.

What I claim and desire to secure by Letters Patent is:-

1. Process for the production of artificial silk or other filaments or threads, or ribbons, tapes,

straws or the like by the evaporative method from solutions of cellulose derivatives comprising extruding a spinning solution into an evacuated zone, leading the extruded product from said zone, and supplying dry air to the region of the point of emergence of said products from the zone so as to prevent the ingress of moist air to said zone.

2. Process for the production of artificial silk or other filaments or threads, or ribbons, tapes, straws or the like by the evaporative method from solutions of cellulose derivatives comprising extruding a spinning solution into an evacuated zone, leading the extruded product from said zone, and supplying dry heated air to the region of the point of emergence of said products from the zone so as to prevent the ingress of moist air to said zone.

3. Apparatus for spinning artificial silk, or other filaments, or threads, or ribbons, tapes, straws, or the like from solutions of cellulose derivatives comprising a spinning cell, a spinning jet in said cell, means for producing a vacuum within the cell, an opening for withdrawing the extruded products from the cell, means for reducing the opening to a small aperture whose size does not substantially exceed the cross-section of the filaments or the like, and means for supplying dry air to the region of said aperture outside the cell.

4. Apparatus according to claim 3, comprising a plate adapted partly to cover the opening whereby the edge of the plate and the edge of the opening form an aperture whose size is not substantially greater than the cross-section of the extruded products, and a hood or cowl adapted to maintain the dry air in the region of the aperture, said hood or cowl being provided with a slot to allow the plate to be moved away from the openmg.

5. Apparatus for spinning artificial silk or other filaments or threads, or ribbons, tapes, straws, or the like from solutions of cellulose derivatives, comprising a spinning cell or chamber, a spinning jet in the said cell, means for producing a vacuum or sub-atmospheric pressure within the cell, an aperture for leading filaments or the like from the cell, and means for supplying dry air to the region of the said aperture to prevent moist air from entering the cell through the aperture.

6. Apparatus according to claim 5 comprising a nozzle adapted to direct a jet of dry air towards the aperture.

7. Apparatus according to claim 5 comprising a cowl-like member surrounding the orifice and adapted to maintain the dry air in the region of the aperture.

8. Process for the production of artificial silk or other filaments or threads, or ribbons, tapes, straws or the like from cellulose acetate comprising extruding a spinning solution into an evacuated zone, leading the extruded product from said zone, and supplying dry air to the region of the point of emergence of said products from the zone so as to prevent the ingress of moist air to said zone.

9. Process for the production of artificial silk or other filaments or threads, or ribbons, tapes, straws or the like from solutions of cellulose acetate comprising extruding a spinning solution into an evacuated zone, leading the extruded product from said zone, and supplying dry heated air to the region of the point of emergence of said products from the zone so as to prevent the ingress of moist air to said zone.

10. Apparatus for spinning artificial silk or 150 form by the apices of the two notches an aperture whose size is not substantially greater than the cross section of the filaments or the like.

11. Apparatus according to claim 10 comprising means adapted to limit the position of the plate, and to allow the size of the aperture to be adjusted.

WILLIAM IVAN TAYLOR.