Spinning device and method having turbulent cooling by blowing

Abstract

The present invention relates to an apparatus for producing continuously molded bodies from a molding material, such as a spinning solution containing cellulose, water and tertiary amine oxide. The apparatus ( 1 ) comprises a die plate ( 3 ) including extrusion orifices ( 4 ) through which the molding material is extruded into substantially filament-like continuously molded bodies ( 5 ). The continuously molded bodies ( 5 ) are passed through an air gap ( 6 ) and guided in a precipitation bath ( 9 ) by a deflector ( 10 ) to a bundling means ( 12 ) where they are united into a bundle of fibers. In the air gap, a blowing means ( 14 ) is provided for directing a cooling gas stream ( 15 ) onto the continuously molded bodies ( 5 ) in a direction transverse to the direction of passage ( 7 ). To improve the spinning stability and mechanical properties of the continuously molded bodies, it is intended according to the invention that the cooling gas stream ( 15 ) is turbulent when exiting from the blowing means ( 14 ).

1 . Apparatus for producing continuously molded bodies from a molding material, such as a spinning solution containing cellulose, water and tertiary amine oxide, comprising a multitude of extrusion orifices through which during operation the molding material can be extruded into continuously molded bodies, a precipitation bath and an air gap arranged between the extrusion orifices and the precipitation bath, and a blowing means for producing a cooling gas streams, the continuously molded bodies being passed during operation in successive order through the air gap and the precipitation bath, and the cooling gas stream being directed in the area of the air gap to the continuously molded bodies, the cooling gas stream being turbulent at least at the exit from the blowing means.  
   
   
       2 . The apparatus according to  claim 1 , wherein the cooling gas stream has a Reynolds number (Re) of at least 2,500 based on its width (B), measured substantially in the direction of passage of the continuously molded bodies through the air gap, and on its velocity in the direction of flow, and the viscosity (v) of the cooling flow medium.  
   
   
       3 . The apparatus according to  claim 2 , wherein the Reynolds number is at least 3,000.  
   
   
       4 . The apparatus according to  claim 1 , wherein the velocity of the cooling stream is at least 30 m/s.  
   
   
       5 . The apparatus according to  claim 4 , wherein the velocity of the cooling gas stream is at least 40 m/s.  
   
   
       6 . The apparatus according to  claim 5 , wherein the velocity of the cooling stream is at least 50 m/s.  
   
   
       7 . The apparatus according to  claim 1 , wherein the width of the cooling stream at the exit is not more than 2 mm.  
   
   
       8 . The apparatus according to  claim 7 , wherein the width of the cooling gas stream at the exit is not more than 1 mm.  
   
   
       9 . The apparatus according to  claim 1 , wherein the specific blowing force of the cooling gas stream is at least 5 mN/mm.  
   
   
       10 . The apparatus according to  claim 9 , wherein the specific blowing force of the cooling gas stream is at least 10 mN/mm.  
   
   
       11 . The apparatus according to  claim 1 , wherein the cooling gas stream His turbulent in the area of the first row of continuously molded bodies on which it impinges.  
   
   
       12 . The apparatus according to  claim 1 , wherein the air gap comprises a first shielding zone by which the cooling gas stream is separated from the extrusion orifices.  
   
   
       13 . The apparatus according to  claim 12 , further comprising apart from the first shielding zone, a second shielding zone through which the cooling area is separated from the precipitation bath surface.  
   
   
       14 . The apparatus according to  claim 1 , wherein the boundary area facing the extrusion orifices and located between the cooling area and the first shielding zone extends substantially in parallel with a plane in which the extrusion orifices are positioned on average.  
   
   
       15 . The apparatus according  claim 1 , wherein the extrusion orifices are arranged on a substantially rectangular base in rows in a direction transverse to the direction of the cooling gas stream.  
   
   
       16 . The apparatus according to  claim 4 , wherein the number of the extrusion orifices in row direction is greater than in the cooling gas stream direction.  
   
   
       17 . The apparatus according to  claim 1 , wherein the precipitation bath has disposed therein a deflector by which during operation the continuously molded bodies are deflected as a substantially planar curtain to the precipitation bath surface, and that outside of the precipitation bath there is provided a bundling means by which during operation the continuously molded bodies are united to form a fiber bundle.  
   
   
       18 . The apparatus according to  claim 1 , wherein the width (D) of the cooling gas stream in a direction transverse to the direction of the passage of the continuously molded bodies through the air gap is larger that the height (B) of the cooling gas stream in the direction of passage.  
   
   
       19 . The apparatus according to  claim 1 , wherein the cooling gas stream (is composed of a plurality of individual cooling gas streams.  
   
   
       20 . The apparatus according to  claim 8 , wherein the individual cooling gas streams are arranged side by side in row direction.  
   
   
       21 . The apparatus according to  claim 1 , wherein the cooling gas stream is designed as a turbulent air flow in the area where the continuously molded bodies Fare passed through the air gap.  
   
   
       22 . The apparatus according to  claim 1 , wherein the cooling gas stream a velocity component oriented into the direction of passages.  
   
   
       23 . The apparatus according to  claim 1 , wherein the molding material prior to its extrusion has a zero shear viscosity of at least 10000 Pas, at 85° C.  
   
   
       24 . The apparatus according  claim 1 , wherein the distance of the cooling area from extrusion orifice in the direction of passage is at least 2 mm each time.  
   
   
       25 . The apparatus according to  claim 1 , wherein the distance I of the cooling area in the direction of passage from each extrusion orifice in millimeters satisfies the following inequality:  
         I>H+A ·[tan(β)−0.14] 
     where H is the distance of the upper edge of the cooling gas stream in the direction of passage from the plane of the extrusion orifices at the exit from the blowing means in millimeters, A is the distance in a direction transverse to the direction of passage between the exit of the cooling gas stream of the blowing means in millimeters and the row of the continuously molded bodies that is the last one in flow direction, in millimeters, and β is the angle in degrees between the cooling gas stream direction and the direction transverse to the direction of passage.  
   
   
       26 . The apparatus according to  claim 1 , wherein the height L of the air gap in the direction of passage in millimeters satisfies the following inequality:  
         L>I+ 0.28 ·A+B    
     where I is the distance of the cooling area from the extrusion orifices in the area where the continuously molded bodies are passed through the air gap, A is the distance in a direction transverse to the direction passage between the exit of the cooling gas stream from the blowing means and the row of the continuously molded bodies that is the last one in flow direction, in millimeters, and B is the height of the cooling gas stream in a direction transverse to the cooling gas stream direction  1  in the direction of passage at the exit of the cooling gas stream from the blowing means.  
   
   
       27 . A method for producing continuously molded bodies from a molding material, such as a spinning solution containing water, cellulose and tertiary amine oxide, the molding material being first extruded to obtain continuously molded bodies, the continuously molded bodies being then passed through and air gap and stretched in said air gap and exposed to a cooling gas stream from a blowing means, and the continuously molded bodies being then guided through a precipitation bath, wherein the cooling gas stream (is put into a turbulent flow state by the blowing means at least at the exit from the blowing means.