US1903622A - Method of producing cellulose articles - Google Patents

Description

r. neon, or cirrcaco, rumors,

Parser OFFER 210], OF CHICAGO, ILLINOIS, A. CORPORATION OF VIRGINIA.

amrnon or rsonuomc cnnm 1 {0 as; ABE! f."

Application fllcfl November 1980. fierial flo. 498,487.

The invention relates to apparatus for producing articles from cellulose and more an ticularly to apparatus for producing cell ose tubes or sausage c s.

In the preferred em odiment of the invention, the cellulose tub is preferably formed from viscose which is obtained by practicing the method briefly described in U. S. Letters Patent No. 1,612,508, granted 1% December 28 1926, to William F. Henderson and Harold Dietrich. The viscose is extruded through an annular orifice and is subjected to one or more solutions so that it again becomes cellulose or cellulose hydrate.

e tubing is then washed in water and sub-' sequently treated with a hygroscopic agent, such as glycerine, to prevent it from drying to such an extent that it willcrack.

e present invention relates particularly to improved apparatus for and an improved method of was in the tubing after it has been ersed in t e hardening solutions.

In practicing the improved method, the tubing is washed in a series of wash tanks holding warm water at difierent temperatures, the arrangement bein such that the tubing is thoroughly close of the byproducts resultin from the reaction oi the viscose and the her ening baths or solutions. The temperature of the water in the several tanks is sucn that the uses evolved do not accumulate more rapidl than they can difiuse through the cellu ose wall and, erefore, there is no excessive overstre I: ct tubing and it is not deformed Other objects and advantages of the inve tion will become apparent as the following detailed description progresses, reference being had to the accompan drawing, wherein:

Figure 1 is a somewhat diagratic V ew of a section taken through apparatus which embodies the invention.

Fig. 2 is an enlarged fragmentary section taken through one of a p urality of wash t shown in Fig. 1, and

Fig. 3 is a die am of electrical apparatus which is utilize to control the temperature of the water in the wash tanks.

the.

apparatus for extruding viscose through an annular orifice to form cellulose tubing which is shown at 11, the tubing being exanon. rem vrsxmc comm-- traded into a coagulating or regenerating hath 13 and being advanced over aroller 14" to a tank 15 holdin a coagulating or regenerating solution. rom the receptacle 15 the tubing is advanced to a receptacle 16 which holds an aqueous solution of the coagulating or regeneratin agents, these agents being carried over mto the solution from the receptacle "15 b the tubing. lhe tubing is then advanced rom the receptacle 16 through a plurality of wash tanks 17, 18, 19 and 20, and thence into a receptacle 21 which holds a hygroscopic agent, preferably glycerine. lldler rolls 23 in the receptacles 15, 16,17, 18 19, 20 and 21 and driven rolls 24 disposed a ove these receptacles guide and advance, respectively, the tubing through the several receptacles.

Various solutions are employed in the eutruding apparatus and in the rece tacle 15 for hardening the viscose. In practicing one embodiment of the invention an aqueous solution of 8 to 10% of sulfuric cold and 12 to 16% of sodium-sulfate is employed in the dium'sulfate is employed in the extrug apparatus, the extruding apparatus being provided with a receptacle 25 which holds 1 these solutions. In the event the second solution is employed in the receptacle 15, a regenerating solution is employed in the rece tacle 15.

e reaction of the acidified salt baths and, the viscose produces several substances, such as sodium sulfate, sodium bisulfate, hy-

drogen sulfide, colloidal sulfur, etc., all of which must be washed out of the regenerated cellulose film before it is dried.

this purpose that the tubing is conveyed through the wash tanks 17, 18, 19 and 20, which tanks preferably hold running water. 10

It isfor '8 leaving the acidified is associated with t Hot water will remove these biroducts from the film or tube much more quic y than cold water. However, if the film or tube is carried into hot water immediately after regenerating bath an result. The acid which e regenerated film soon lmparts a permanent acidity to the water in the first wash tank if the water is not changed often enough to prevent such acidity. If the temperature is high, this acid exerts a weakening effect on the cellulose film. Volatile substances formed by the action of the acid on the viscose are quickly driven out of the film when it is immersed in hot water, and, under certain conditions, may cause minute as bubbles to be formed in the film itself. ese volatile substances are probabl hydrogen sulfide, carbon disulfide and car on dioxide. The production of these volatile biproducts resents the greatest difficulty when the ce ulose product is in the form of a seamless tube. Here, a substantial rise in temperature following the regenerate or cellulose when the tube is lead into hot water causes an inflation of the tube by the gases trapped inside. Under these conditions, the gases accumulate more rapidly than they can diffuse through the cellulose wall and serious overstretching and deformation results.

Regenerated cellulose films are subject to severe shrinkage during the regenerating operation and during subsequent washing stages, and the use of hot water accelerates this shrinkage. The application of hot water immediately after the acid treatment causes such severe and sudden shrinkage that frequent breakage may occur.

The present invention permits the use of hot water for washing the regenerated cellulose films or tubes without encountering the difliculties mentioned above. Thus, the temperature of the water in the wash tanks 17, 18, 19 and 20 is adually raised, beginning with water at a ut the same temperature as that maintained in the acid tank and ending in the final wash tank 20 with hot water. In a preferred embodiment of the invention, the water in tank 17 is held at approximately 20 0., the water in the second tank .18 is held at about 30 C., the water in the tank 19 is held at about 35 C., and the water in the tank 20 is held at 50 0., or even higher.

As indicated above, the water in the tanks 17, 18, 19, and 20 is preferably; changed at frequent intervals or continuous thus pipes 17a, 18a,19a and 20a are adapted to discharge water into the receptacles 17 18, 19 and 20, respectively, the overflow being carried off by pipes 17b, 18b, 19b and 206, respectively. If it is so desired, each of the tanks 17, 18, 19 and 20 may be connected to a larger tank so that the water may becirculated continuously. Such construction permits the teminferior product ma perature of the water to be readily controlled.

In the preferred embodiment of the invention, means is preferably associated with each of the tanks 17 18, 19 and 20 to control the temperature of the water therein. In this instance, the controlling means comprises heating devices 30, 31, 32 and 33 disposed in the tanks 17, 18, 19 and 20, respectively, the heating devices being preferably electrical resistances. The resistances are connected to a suitable source (not shown) of electrical energy, as illustrated in Fig. 3. The resistances 30, 31, 32 and 33 are controlled by thermostatic devices 35, 36, 37 and 38, respectively, which are preferably identical in construction. The thermostatic device 35 is illustrated in detail in Fig. 2 and comprises, in this instance, a diaphra 39 holding a quantity of some suitable v0 atile fluid which will expand when it is heated. The diaphragm is carried by a bracket 40 mounted in the tank 17 the diaphragm being positiqfipd beneath the surface of the water in the ta v The free end of the diaphragm 39 is connected by a post 41 to a lever 42 which is pivoted intermediate its ends to a bracket 43 carried by the tank 17. A member 44, depending from one end of the lever 42, is adapted to depress a metallic spring member 45 when the diaphragm 39 expands. The spring member 45 carries a contact point 46 engageable with a contact point 47 carried by a spring member 48. The spring members 45 and 48 are insulated from each other and are mounted in a housing 49 secured to a wall of the tank 17. A set screw 50 screw-threaded through one of the walls of the housing 49 engages the spring member 48 and is adapted to bring it into a plurality of adjusted positions. Thus, the spring member 48 tends to flex in an upward direction and the screw 50 may be manipulated against this action to bring the contact point 47 into any desired position with respect to the contact point 46. The spring mem er 45 also tends to. spring upward so as to bring the contact point 46 into engagement with the contact point 47. Obviously, the apparatus may be adjusted in such manner that the circuit through the re sistance 30 may be closed unless the water in the tank 17 is at least 20 0., or any other temperature that may be desired.

The thermostatic devices 36, 37, and 38 are adjusted to maintain the temperatures noted above in the tanks 18, 19 and 20, respectively, or any other temperatures that may be desired.

Briefiy,in the operation of the above described ap aratus, the tubing 11 passes from the extru ing mechanism 10 through the tanks 15 and 16 into the first wash tank 17 and thence through the wash tanks 18, 19 and y in the tanks 17, 1'8, 19 and 20 is contrenee gt;

' the thermostatic devices 35, 36, 37 and respectively, in the manner describedabove so that the casing or tubing is not sub'ected 5 to a high temperature immediately a r it reaches the tank 16, but is gradually subjected to hi her temperatures until it has een thoroug 1y washed.

While I have shown and described certain 19 embodiments of my invention, it is to be 'un- V ders'tood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims,

in which it is my intention to claim all novel ty inherent in an invention as broadly as possible, in view 0 the prior art.

' I claim:

20 1. The method of forming a cellulose product, which method comprises extruding viscose and regenerating it and subjecting the regenerated viscose to several baths of heated water of increasing temperature.

2. The method of forming a cellulose prodnot, which method comprises extruding viscose, regenerating it, and washing the regenerated substance in several baths of heated water of increasing temperatures, one of said baths beilag maintained at a temperautre less than 409 and another of said baths be' gairgained .at a temperature in excess 0 3. The method of forming a cellulose prodnot, which method comprises extruding viscose, regeneratingsaid viscose, and washing the regenerated substance in at least three baths of heated water of increasing temperatures, at least one of said baths being main- 40 tained at a temperature in excess of 35 C.

In testimony whereof, I hereuntov afliz; mysignature this 24th day of October, 1930.

wILLmM r. ENDERSON.

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