US1944378A - Process and apparatus for producing dull luster rayon - Google Patents

Description

Jan. 23, 1934. R, A, J. THENOZ PROCESS AND APPARATUS FOR PRODUCING DULL LUS TER RAYON Filed Jan. 24, 1930 Patented Jan. 23, 1934 r UNITED STATES PROCESS AND APPARATUS FOR PRODUC- ENG DULL LUSTER RAYON Raymond Alfred Joseph Thenoz, Milan, Italy,

assignor to Ruth-Aldo Company, Inc., a corporation of New York Application January 24, 1930, Serial No. 423,166, and in Italy July 16, 1929 Claims. (01. 18-8) This invention is a novel improvement in the dull luster filaments produced in accordance with production of so-called artificial silk commonly my invention. called rayon from cellulose esters such as celluit is well known that certain forms of artificial lose acetate or cellulose nitrate. The object s11 commonly known as rayon, are made by I of the invention is to produce a dull luster rayon forcirig a solution of cellulose nitrate, cellulose 6t) and this is accomplished by so forming the filaace a e, or other ester of cellulose, dissolved in ment that it will have more than two re-entrant a volatile solvent through very fine apertures in reflective surfaces though it may vary in contour a spinneret and evaporating the solvent from of its cross section at difierent portions of its the us formed filaments by means of heated 10 length. This result is obtained by my novel esso that the filaments-are eventually submethod of and apparatus for treating the filament i r l y f ed 1from solvent and are hardened during the spinning thereof. The invention in- 3 S110 ove of the solvent. The gases emcludes a novel process for spinning such filament, ployed may atmofiipherlc 0 t e novel apparatus for use in h peratjgn, d aseous medium or mixtures thereof suchas are 15 commonly employed in the art-and I will hereg g s gfig ggg gf igg g gg 131.01% inafter refer to them by the inclusive term gas erties of rayon as heretofore produced has been or gases. A num er of such filaments assembled the high luster or" the thread or fabric'believed togemer a a thread of rayon. For example I: 1 to be due to the reflection oilight from the head a 5011mm of cellulose acetate d sn t 'des of the individual filam nts which form solvedacebone can be used for the Spmmne filread Attempts reduge the reflective solution and fed to the spinneret and is ejected Such hi luster rayon have baen ugh the orifices 01" the spinneret as filaments rifgg irl i ia ious ways' for xample by ntroduca i g g fi g f thus P 'ucing amenso ceuoseaceae. mg plgment by h 1 z?' m for I have discovered that by artificially producing mughemngihe Surface m 0 Her Ways a shifting or movement of gases at an angle to I have novel i f f fi the path of the jets adjacent the spinneret and paratus. f producing dun t myon if before the filaments harden the cross section of may readlly be adapted? use m n facto 16s the filament can be varied and rendered irregular now equipped for making rayon yarn. To enand uneven in contour. This may be due to evapable others to understand 3 the mveniwn oration oi the solvent from each jet issuing from I will describe the same with reference to the t Spjnneret ccurring unevenly on different acc p y g drawing, and then Set forth in the sides of the filament due to the diiierences in presclaims the essentials of the invention and the sures thereon, or t may t place more rapidly 5 n v p ss, product and appa atus embraced at the one side of the filament-than from the within the ti n, other side, resulting in a different thickening of In said drawing the cellulose ester film or skin formed on the Fig. l is a diagrammatic view of a typical exterior of the filament at the beginning of evapheated spinning cell as used in the dry spinoration from the filament and consequently pro- 40 ning process of manufacturing filaments from ducing varying irregular cross sectional contours solutions of cellulose esters in volatile solvents of the filament. except that a fan has been added; Hitherto, the rule, desire, and purpose in the Fig. 2 is a greatly magnified View of a single industry has been to evaporate the solvent from orifice of the spinneret and a filament. issuing the-filaments as uniformly as possible on all sides 45 therefrom. I thereof, so that cross sections of the filament Figs. 3, 4, 5 and 6 are diagrammatic transverse would be alike throughout and alike in difierent sections of the filament as ordinarily produced filaments. The only exceptions have been on respectively taken on the lines 3--3, 4-4, 55, 7 occasions when asan undesired violent air ourand 6-6, in Fig. 2. 7 rent has struck the filament in its semi-hardened 50 Fig. '7 is a greatly enlarged diagrammatic sec state due to poor construction of the cell or when tional elevation on the line '77 in Fig. 1 showsome port in the cell has been opened causing ing the high luster filaments produced by an oran alteration in the composition of the gases dinary cell operating under the old method. therein or deflection of the filaments. In such Fig. 8 is a similar greatly magnified similar secundesired exceptional and accidental cases and 55 tion on the line 77 in Fig. 1 illustrating the times the evaporation does not take place with the desired uniformity and the filaments produced under such circumstances have been considered imperfect and undesirable.

I have discovered that by varying the lateral pressure of the gases on the filament during initial formation by imparting a movement to the gaseous atmosphere in a direction perpendicular, or inclined, to the length of the filament, and at a point adjacent the spinneret and before the filament has been solidified, I canproduce such irregularities in the cross section of the filament that as a result, light, instead of being entirely reflected, is partly difiused and only partly reflected thereby, which effect is not obtainable with currents of gas travelling only parallel to the main movement of the filament and only in either the same or the opposite direction of movement of the filament.

The process may readily be carried on in a cell or chamber such as is commonly employed with a slight modification of or addition to such chamber as hereinafter explained.

-A simple means for producing the desired cur rent of gas is to place a small fan at the side of the spinning cell at a height just below the level of the spinneret. The concentration of the solvent in the gas about the spinneret will be changed but slightly if at all, because the fan merely forces or deflects a part of the gas in or passing through the cell laterally againstthe filament near the spinneret and may be said to cause a lateral air bump or curve in the air current normally traversing the cell in a direction parallel with the filaments but usually moving in a direction opposite thereto.

In the diagram Fig. 1, a indicates an ordinary spinning cell having double walls I) through which hot water or steam or other source of heat circulates; c and d are the inlet and outlet, respec tively, for the gas supplied to the cell and by which the volatile solvent in the filaments is evaporated; and f is the spinneret located in the cell and constructed and operated in the usual manner. Such cells are commonly provided with ,ports for cleaning the spinneret, and means to control the temperature, the circulation of gas and to recover the volatilizedsolvent, etc. all of which are well known in the art and therefore not described.

Figure 2 represents a diagrammatic greatly magnified view of one of the orifices A of the spinneret f of any suitable kind, from which the cellulose ester solution, known as collodion, is issuing, and shows how the composition of the filament changes progressively as it leaves the spinneret. Figure 3 shows a cross section of the filament on the line 33, Figure 2, operated in the usual manner, such filament being first tubular and having an exterior film e of partially solidified cellulose ester with an unchanged solution of cellulose ester in'its interior. As the solvent evaporates, the exterior film e thickens and the amount of collodion in the interior decreases, due

. to the evaporation. This results in a partial collapse of the tubular film e in the same manner as alight walled rubber tube collapses under a partial vacuum. This stage is indicated in Fig. 4, which represents a cross section on the line 44,

Fig. 2. Further evaporation of the solvent in the filament produces further contraction, as indicated in Fig. 5, which represents a cross section on line 55 in Fig. 2. When the solvent is all substantially evaporated by the usual process the .3 filament is a flattened ribbon Whosecross section is indicated in Fig. 6, which is a cross section on the line 6-6 in Fig. 2.

The aforesaid consecutive changes in cross section take place and give the final cross section 9 (Fig. 6) when evaporation of the solvent proceeds uniformly according to the old methods hitherto used in spinning rayon filaments.

Figure 7 illustrates greatly magnified typical cross sections of filaments obtained by operating the spinning cell as hereinbefore customarily used in the industry; while Fig. 8 illustrates greatly magnified cross sections of filaments produced in the same spinning cell operated and equipped in accordance with my invention.

In my invention a spinning cell is provided with means adjacent the spinneret for producing a lateral deflection of the gaseous current or a subsidiary internal lateral gas current within the main gas current in the cell at an angle to the filaments adjacent the spinneret so that the filaments issuing from the spinneret will be subjected to lateral gascurrents-whereby they are caused to assume irregular shapes in cross section during the hardening thereof as indicated in Fig. 8. A very simple means (shown diagrammatically in Fig. 1) is a small rotary screw or fan h, placed in the interior of the spinning cell a adjacent and to one side of the spinneret which fan can be operated by any suitable means so as to produce a current of gas or deflection of gases in a direction inclined to the collodion filaments issuing from the spinneret.

Such lateral current or deflection of gas will so affect the evaporation of the solvent from the V filament during the formative and hardening steps that instead of contracting regularly and uniformly, as in Figs. 3-6 it will contract irregularly and will have irregular and re-entrant surfaces as indicated at g in Figure.8, whereby the light is partially reflected but more largely .diffused by such surfaces. Consequently the resulting filament and the yarn and fabrics producedfrom such filament do not have the high luster of ordinary rayon but instead have a dull luster which is so much desired in present day fabrics. The tensile strength of the dull luster filaments obtained by my invention is essentially the same as that of filaments produced by the old processes. 7

It is not considered that each filament will have one and the same type of cross section throughout its length. Instead any single filament may have various cross sections at different parts of its length, and probably no two filaments will be exactly alike in cross section, as indicated in' o Fig. 8.

In the claims the term gas is intended to include, not onlyatmospheric air, but also any gas, or mixture of gases, or of air and gases, or any one of these which will carry away solvent evaporated from the collodion.

The lateral deflection of the gaseous currents adjacent the spinneret does not disturb the equilibrium conditions of the cell, and it is not necessary to admit thereto or carry away therefromany other gas than would be used in the ordinary spinning process, nor to affect the pressure or concentration of the solvent or gases used in spinning the filament.

In other words the invention is applicable to the ordinary spinning cell, and the temperatures, flow of gases to and from the cell, the gas employed in the cell, and the quality of the solutions employed in forming the filament can remain as ordinarily used, and the cell can 'be led operated under just the same conditions to produce my improved filament as it is operated to produce the ordinary filament provided only that suitable means are employed to produce the lateral deflection of the gaseous current or varying pressures against the filaments in the formative steps thereof; and while I have shown and described a fan in the cell as the means for producing such deflection of the current or unequal pressures the invention is not restricted to such means.

I claim:

1. A process of producing low luster rayon in which the filament while in plastic condition is subjected to the impact of a transverse current of gas at a velocity sufl'icient to produce a substantial permanent deformation of the contour of the filament.

2. A process of producing low luster rayon in which the filament immediately adjacent a spinneret is subjected to the impact of a transverse current of gas at a velocity sufiicient to produce a substantial permanent deformation of the contour of the filament.

' 3. A process as set forth in claim 1 in which the current of gas impinges on the filament substantially at right angles thereto.

4. A process of producing low luster rayon by spinning in a closed. cell containing a gas in which the solvent vaporizes, including the production within the cell of a current of said gas impinging transversely on the filament in a zone where said filament is in plastic condition, and at a velocity sufiicient to produce a substantial permanent deformation of the contour of said filament.

5. In apparatus for dry spinning rayon filaments, a spinning cell of the closed type adapted to retain gas in which the solvent vaporizes, a spinneret adjacent an end of the cell, and rotary fan means within the cell for creating in said gas adjacent'the spinneret a transverse current directed across the path of the filaments adjacent the spinneret at a velocity sufilcient to produce a substantial permanent deformation in the contour of the filaments.

RAYMOND ALFRED JOSEPH THENOZ.

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