US2142121A

US2142121A - Manufacture of artificial filaments, ribbons, films, and like materials

Info

Publication number: US2142121A
Application number: US62332A
Authority: US
Inventors: Dreyfus Henry
Original assignee: Henry Dreyfuss Associates LLC
Current assignee: Henry Dreyfuss Associates LLC
Priority date: 1935-03-20
Filing date: 1936-02-04
Publication date: 1939-01-03
Anticipated expiration: 1956-01-03
Also published as: GB453869A

Description

H. DREYFUS Jan. 3, 1939.

MANUFACTURE OF ARTIFICIAL FILAMENTS, RIBBONS, FILMS, AND LIKE MATERIALS Filed Feb. 4, 1936 F/GZ 5 U S u & w mm D 6 w A w A A M. W \e H 0 v Patented Jan. 3, 1939 UNITED STATES MANUFACTURE OF ARTIFICIAL FELAMENTS, RIBBONS, FHLMS, AND LIKE MATERIALS Henry Dreyfus, London, England Application February 4, 1936, Serial No. 62,332 in Great Britain March 20, 1935 12 Claims.

This invention relates to improvements in the manufacture of artificial materials and is more particularly concerned with new processes for the manufacture of filaments and threads of cellulose acetate or other organic derivatives of cellulose or other organic thermoplastic filament forming substances. The process is also valuable for the manufacture of ribbons, foils, films and like materials from said substances.

According to the present invention, filaments, threads, ribbons, foils, films and the like of the above character are manufactured by spinning a solution of the cellulose derivative or of other organic thermoplastic filamentor film-forming 15 bases into steam under pressure at a temperature of above 100 C. so as to produce an evaporation of the solvent content of the solution and, at

the same time, to maintain the structural conti-,

nuity of the filaments, foils, etc. It is of great advantage that the steam be wet or just saturated, and it is also important that its temperature should be adjusted so as not to destroy the continuity of the structure. Thus generally the temperature should be at least as high as that necessary to render the cellulose derivative or other base plastic. In the case of acetone-soluble cellulose acetate the temperature is preferably above 120 C.

If a solution of cellulose acetate in acetone be spuninto a chamber into which steam is injected at atmospheric pressure, the steam cools and the result is either a discontinuous mass om material, or filaments or other products which are delustred and are discontinuous in structure. If, however,

"the temperature of the steam be increased. preferably while maintaining the steam wet or just saturated, a point is reached at which the structure of the filament or other material remains continuous. The product may be of moderate or 40 high lustre and in addition a considerable drawdown may be applied to the filaments or other materials without breakage.

The process of the present invention presents very substantial advantages over the existing manufacture of such materials. Evaporation of a given volatile solvent may be effected in a much shorter time and consequently much shorter spinning chambers may be used and/or much higher spinning speeds attained. Further, a proper adjustment of the temperature of the steam in relation to the particular dope which is being spun enables a very considerable draw-down to be applied during the manufacture of the filaments or other materials, and in consequence filaments or other materials of very high tensile strength may be produced. In addition, the new process is of great advantage from the point of view of solvent recovery. The spinning chambers need only be provided with suitable condensing apparatus to enable the solvent to be readily recovered With- 0 out the aid of elaborate solvent recovery plant.

As previously indicated, it is highly advantageous for the purpose of the present invention to employ the steam in a saturated or wet condition and to employ it at a temperature well above the boiling point of water at atmospheric pressure. Thus, for instance, the steam may be at a temperature of 0., C., C. or C. or more, and at the appropriate pressure for the steam to be saturated or wet, such as 10, 20, 30 pounds or more per square inch above atmospheric pressure. The best conditions are dependent upon the particular dope which is being spun, including the particular cellulose derivative or 20 other filamentor film-forming base, and the nature of the volatile solvent, upon the rate of spinning and upon the degree of stretch which is being applied during the spinning.

The steam may contain vapours of acetone, di- 25 oxane or other volatile solvent or softening agent for the cellulose derivative or other filamentor film-forming base and the presence of such vapours may lower the temperature at which it is necessary to operate to secure the best physical 80 properties in the products. Generally quite low proportions of vapour are sufiicient for this purpose, for example proportions by volume of less than 10% and preferably under 5%.

The process of the invention may be carried out 35 in a spinning cell or chamber adapted to with stand pressure, and for this purpose a tubular chamber is best, spinning nozzles or slits being provided at one end of the chamber. The chamber is also provided with means for supplying 40 steam under pressure, and with means for with drawing steam containing the vapours of the volatile solvent. Preferably the chamber is further fitted with a pressure gauge, a pressure relief valve and a drain pipe for condensed steam. It 45 is preferred to wind the filaments or other products outside the chamber, and the size of the outlets for the filaments etc. is preferably adjusted so that escape of steam is reduced to a minimum. The steam inlets may be arranged at any suitable 50 points in the spinning chamber, though it is preferred to admit some saturated or wet steam in the neighbourhood of the spinning nozzles.

The spinning nozzles may be arranged with respect to the spinning chamber so that they are be just inside the chamber or terminate at one end of the chamber, so as to avoid substantial heating of the dope by the pressure steam in the chamber, and filter candles, pumps and other devices associated with the extrusion devices may be located entirely outside the spinning chamber, or alternatively the filter candle and extrusion device may be so adjusted with respect to the spinning chamber that any desired degree of heat is imparted by the steam to the dope.

The most advantageous arrangement is to have the extrusion device just projecting into the steam chamber and to have the remainder of the extrusion device and its associated filter candle, with or without the spinning pumps or other devices for delivering the dope to the extrusion orifices in a regulated quantity, in a separate chamber where the dope may be suitably attemperated before spinning. The separate chamber may be supplied with water, oil or other attemperating fluid to bring the dope to the required temperature at the spinning point. Such an arrangement is illustrated, in conjunction with ordinary cells for spinning into air, in U. S. application S. No. 375,151 filed July 1, 1929. Alternatively, the filter candle may be jacketed so as to attemperate the spinning dope.

In Working the present invention, for example by spinning a solution of cellulose acetate into steam under pressure, the spinning operation may be started in air at atmospheric pressure to facilitate leading the filaments or other materials out of the spinning chamber, and the air may be replaced by the steam under pressure. The spinning apparatus may be provided with any of the usual devices in the art, such as a godet to control the draw-down and suitable winding apparatus or twisting and winding apparatus for the filaments or other materials.

The present invention further includes a process in which the spinning is carried out partly in air or other gas and is continued in steam under pressure. For example, spinning may be conducted in the usual way until the filaments or other materials are solid but have not been deprived of all their solvent, and the solventcontaining filaments or other materials then carried into a steam chamber where they may be stretched and the remainder of the solvent re- 1 moved therefrom. The spinning cell may, for

example, be partitioned so as to contain air or other gas in the portion carrying or containing the extrusion device and so as to contain steam under pressure in the portion remote from the extrusion device. Here again, the entire spinning operation may be started in air or similar gas and the air or other gas in the portion of the chamber remote from the nozzle replaced by steam.

In order to avoid injection of the steam from the steam chamber into the chamber in which the dope is actually extruded, the air or other gas in the latter chamber may itself be under pressure, preferably at a pressure substantially equal to the steam pressure. In this form of the invention, the orifices leading from the air or gas chamber to the steam chamber, as Well as the outlet orifices from the steam chamber, may be made adjustable so as to be capable of being closed somewhat after spinning has been start- As previously indicated the new process enables very considerable draw-down to be applied.

to the filaments and like materials. The tension for producing the draw-down may operate upon the more or less solidified filaments or like materials directly from the extrusion device or means may be adopted, such as a gate tension device, to restrict the tension or part of the tension to portions of the filaments or other materials in the later stages of the spinning operation.

The process of the present invention may be applied to the manufacture of filaments, threads, ribbons, foils, films and the like of cellulose acetate, or of any other organic ester or ether of cellulose, for example cellulose formate, cellulose propionate, cellulose butyrate, cellulose nitro-acetate, methyl, ethyl or benzyl cellulose, or other organic filamentor film-forming bases, for example poylvinyl acetate and other polyvinyl compounds. The filamentor film-forming base may be dissolved in any suitable volatile solvent, for example acetone, methyl ethyl ketone or other ketones; methylene ethylene ether, dioxane or other cyclic ethers; or methylene chloride, ethylene chloride, chloroform, tetrachlorethane or similar chlorinated hydrocarbons or mixtures thereof with small amounts of alcohol.

The boiling point of the solvent used in the dope may, where it is desirable, be suitably related to the temperature of the steam used in the spinning cells. Thus where the temperature of the steam is considerably above the boiling point of the solvent, say 30 C. or more, there may be a tendency towards the production of hollow filaments or like products, so that, by a suitable correlation of the boiling point of the solvent with the steam temperature, completely solid filaments may be produced or filaments which are more or less hollow or voluminous.

The water-soluble solvents may, in general, be separated from the condensate by a simple distillation process. Water-insoluble solvents present the advantage that they separate from the water in the condenser as a separate layer and may be drawn oif for direct re-use.

The accompanying drawing illustrates suitable forms of apparatus for carrying out the process of the invention, Fig. 1 illustrating an apparatus in which the entire spinning operation is carried out in steam under pressure, and Fig. 2 an apparatus in which the first part of the spinning operation is conducted in compressed air and the remainder in steam under pressure.

Referring to Fig. 1, a chamber 3 is fitted with a supply pipe 4, filter candle 5 and spinning jet 6. The filaments l, extruded from the jet 6, pass down the tubular cell 8 inside a casing 9 forming an extension of the chamber 3 and constituting therewith an outer chamber enclosing the candle 5 and jet 6 and the cell proper 8. The filaments leave the cell 8 through a perforation in a closure plate [0 and pass thence to the godet ll and are twisted and wound by means of a cap spinning device 12. The cell B is supplied with steam from a main l3 through branch pipes l4 fitted with valves 15, the steam being injected into the cell 8 through perforated annular pipes IS. The cell 8 is provided with a pipe I! fitted with a valve i8 for Withdrawing steam containing solvent vapours, with a valved drain pipe I9, a pressure gauge 20, and a pressure relief valve 2|. Inside the casing 9 are provided steam heating pipes 22.

The upper end of the cell 8 is closed by means of a hood 23 pressed down upon a pad of packing material 24 and making a tight joint with a tubular member 25, fitting round the filter candle 5. Access to the spinning jet 6 is obtained through a door 26 in the chamber 3 and by unscrewing and raising the hood 23. A jacket 4'! is provided round thefilter candle 5 and is fed with an attemperating fluid passing from a main 2! through a valve 28, through an inlet pipe 29 into the jacket, and out by a pipe 3!] and valve 3| into an exhaust main 32. The chamber 3 is further provided with a suction draw-ofi 34.

In starting up the apparatus, the closure plate ii! is opened slightly, steam turned'on in the heating pipes 22, and the hood23 raised. A slow current of air is sucked through the apparatus by means of the suction pipe 34, the heated air traversing the cell 8 serving to evaporate volatile solvent so that by the time the filaments reach the foot of the cell they aresuificiently solid to be handled. The spinning thus started, the fila ments are threaded through the outlet hole in the plate it, and the plate screwed in position. Steam is then turned on slowly into the cell 8, the valve l8 being slightly open, and the hood .23 screwed down to make a pressure tight joint with the pad 24. The steam is turned off from the pipes- 22, and the steam pressure in the cell 8 gradually increased, the filaments being drawn out more and more rapidly from the chamber. When the desired spinning speed is attained, the filaments are carried round the godet roller H and thence to the cap spinning device I2.

Referring to Fig. 2, the filter candle 5 is con tained in a chamber 35 forming an enlargement of the upper end of the tubular cell. The latter is formed in two

parts

36, 31, the upper part 36 being surrounded by a chamber 38 forming an extension of the upper chamber 35, and provided with heating pipes 22. Access to the spinning jet 5 is obtained through a door 39 forming a gas tight joint on a gasket 40. The spinning solution passing through the candle 5 is heated by means of a heating coil 4| connected to the supply and

exhaust headers

21 and 32 for heating the fluid. Between the

parts

38 and 31 of the tubular cell, a perforated plate 42 is provided. The upper part 35 of the cell is provided with a valved inlet 43 for compressed air and a pressure gauge 44.

In operation the spinning is started up in air at atmospheric pressure, as described with reference to Fig. 1. When spinning is well started, the filaments are threaded through the plate 42 and the closure plate Hi, and the lower part 31 of the cell fixed in position. Compressed air is then turned on through the pipe 43 and steam through the pipe l3 so that the lower part 31 of the cell is filled with steam under pressure, and the upper part of the cell 35 and the upper chamber 35 filled with compressed air. Steam and solvent vapour escape as before through the pipe ii, and air and solvent vapour through the pipe 34.

If desired, either in the apparatus illustrated in Fig. 1 or in that illustrated in Fig. 2, a gate tension device may be provided so as to prevent all or part of the tension being operative upon the filaments for the whole of their travel through the cell. Such a device is illustrated at 4-5, Fig. 2.

The following examples illustrate the invention but are not to be considered as limiting it in any way.

Example 1 A 25% solution of cellulose acetate in dioxane is spun into filaments, using either the apparatus illustrated in Fig. 1 or that illustrated in Fig. 2. In both cases the pressure of the steam is adjusted so that its temperature is 125-135 C. and the steam is just wet, and in the case of Fig. 1 they dope temperature is adjusted so that it is mil-105 C. In the case of Fig. 2, the air temperature and the dope temperature are both adjusted to this figure.

Example 2 A 20-24% solution of cellulose acetate in the monemethyl ether of ethylene glycol is spun as described in Example 1, with the steam temperature at l-135 C.

Example 3 The process is carried out as in Example 2, with the exception that the spinning solvent consists of 80 parts of the methyl ether of ethylene glycol and 20 parts of methyl glycol mono-acetate.

Example 4 A 25% solution of cellulose acetate in a mixture of 80% of the monomethyl ether of ethylene glycol and 20% of acetone is spun as described in the preceding examples, the temperature of the steam being 120-125 C. and the steam is just wet.

In all cases, a very considerable draw-down is obtained and the filaments of medium to high lustre possess a high tenacity.

Having described my invention what I, desire to secure by Letters Patent is:

1. Process for the manufacture of filaments, threads, ribbons, foils, films and the like, which comprises spinning a solution of an organic thermoplastic filamentor film-forming substance into an evaporative atmosphere which is heated and which is maintained under superatmospheric pressure, said evaporative atmosphere comprising, during at least part of the spinning operation, steam at above 100 C. and at superatmospheric pressure.

2. Process for the manufacture of filaments, threads, ribbons, foils, films and the like, comprising spinning a solution of an organic thermoplastic filamentor film-forming substance in a volatile solvent into steam at above 100 C. and at superatmospheric pressure, and drawing out the products during the spinning.

3. Process for the manufacture of filaments, threads, ribbons, foils, films and the like, comprising spinning a solution of an organic thermoplastic filamentor film-forming substance in a volatile solvent into heated air at superatmospheric pressure and before the volatile solvent is removed carrying the products into steam at above 100 C. and at superatmospheric pressure, and drawing out the products.

4. Process for the manufacture of filaments and threads of organic derivatives of cellulose, which comprises spinning a solution of an organic derivative of cellulose in a volatile solvent into wet or saturated steam at above 100 C. and at superatmospheric pressure, and drawing out the products.

5. Process for the manufacture of filaments and threads of cellulose acetate, which comprises spinning a solution of cellulose acetate in a volatile solvent into wet or saturated steam at above 100 C. and at superatmospheric pressure, and drawing out the products.

6. Process for the manufacture of filaments and threads of cellulose acetate, which comprises spinning a solution of cellulose acetate in a volatile solvent into wet or saturated steam at above 120 C. and at superatmospheric pressure, and drawing out the products.

7. Process for the manufacture of filaments and threads, which comprises spinning a solution of cellulose acetate in a volatile organic solvent having a boiling point of C. or above into Wet or saturated steam at a temperature above C. and at superatrnospheric pressure, and drawing out the products.

8. Process for the manufacture of filaments and threads, which consists in spinning a solution of cellulose acetate in a volatile solvent having a boiling point of 100 C. or above into heated air at superatmospheric pressure and thence into wet or saturated steam at above 120 C. and at superatmospheric pressure, and drawing out the products.

9. Process for the manufacture of filaments and threads, which consists in spinning a solution of an organic derivative of cellulose in a volatile solvent into wet or saturated steam at above 100 C. and at superatmospheric pressure, and drawing out the products while preventing the whole drawing tension from operating upon the materials at the point of extrusion.

10. Process for the manufacture of filaments and threads, which consists in spinning a solution of cellulose acetate in a volatile solvent into wet or saturated steam at above 100 C. and at superatmospheric pressure, and drawing out the products while preventing the whole drawing tension from operating upon the materials at the point of extrusion.

11. Process for the manufacture of filaments and threads, which comprises spinning a solution of an organic derivative of cellulose in a volatile solvent into heated air at superatmospheric pressure and thence into wet or saturated steam at a temperature above 100 C. and at superatmospheric pressure, and drawing out the products while preventing the whole drawing tension from operating upon the materials at the point of extrusion.

12. Process for the manufacture of filaments and threads, which comprises spinning a solution of cellulose acetate in a volatile solvent into heated air at superatmospheric pressure and thence into wet or saturated steam at a temperature above 100 C. and at supera'tmospheric pressure, and drawing out the products while preventing the whole drawing tension from operating upon the materials at the point of extrusion.

HENRY DREYFUS.

CERTIFICATE, OF CORRECTION. Patent No. 2,1L .2,l2l'. I January 5, 1959.

HENRY DREYFUS;

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correotionas follows Page 1, first column, line 52, for "om" read of; page 5, second column, line 17, Example 2, after "155 0." insert the words and period and the steam is just wet.;

and that the said Letters ,Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of February, A.-D. 1959.

Henry Van Arsdale (seal) Acting Conmaissioner of Patents.