Melting and spinning device and melting and spinning method

Abstract

The present invention is relative to a melt spinning apparatus for melt spinning a biodegradable polymer material. The biodegradable polymer material is melted by a melt mechanism ( 4 ) including a screw ( 16 ) which is mounted in a vertically mounted cylinder ( 8 ) coaxially with the cylinder ( 8 ) and which is rotationally driven by a rotational driving mechanism ( 7 ). The screw includes at least one turn of a helical groove ( 17 ) on its peripheral surface. The biodegradable polymer material being melted in this way is discharged in the vertical direction from a discharge opening of a nozzle ( 10 ) mounted coaxially on the cylinder ( 8 ).

1 . A melt spinning apparatus for melt spinning a strand of a biodegradable polymer material, forming a stent implanted in a living body, comprising: 
 a vertically mounted cylinder, supplied with said biodegradable polymer material;    a screw mounted in said cylinder coaxially therewith, said screw being rotationally driven by a rotational driving unit and having at least one turn of a helical groove on its peripheral surface; and    a nozzle mounted to the distal end of said cylinder and having a discharge opening coaxially with said cylinder;    said biodegradable polymer material supplied into said cylinder and melted by rotation of said screw being emitted vertically from a discharge opening in said nozzle for spinning the strand.    
     
     
         2 . The melt spinning apparatus according to  claim 1  wherein a sole discharge opening is provided in said nozzle for extending in the vertical direction for spinning a filament.  
     
     
         3 . The melt spinning apparatus according to  claim 1  further comprising a plurality of heating units in juxtaposition along the axial direction of said cylinder, with the heating temperature of said heating units being controlled independently of one another.  
     
     
         4 . The melt spinning apparatus according to  claim 2  further comprising heating units on the outer periphery of said nozzle for controlling the nozzle temperature.  
     
     
         5 . The melt spinning apparatus according to  claim 1  wherein the helical groove formed on the peripheral surface of said screw is formed to a pitch smaller than one-half the screw diameter.  
     
     
         6 . The melt spinning apparatus according to  claim 1  further comprising a supplying unit for loading a biodegradable polymer material into said cylinder and temperature controlling mechanism for controlling the temperature of the biodegradable polymer material charged into said supplying unit.  
     
     
         7 . A method for melt spinning a strand of a biodegradable polymer material, forming a stent implanted in a living body, comprising: 
 melting the biodegradable polymer material by a melt mechanism including a screw which is provided in a vertically mounted cylinder coaxially therewith and on the peripheral surface of which at least one turn of the spiral groove is formed, said screw being rotated by a rotational driving mechanism;    the molten biodegradable polymer material being emitted in the vertical direction through a discharge opening in a nozzle provided coaxially with said cylinder for spinning the strand.    
     
     
         8 . The melt spinning method according to  claim 7  wherein the molten biodegradable polymer material is emitted in the vertical direction from a sole discharge opening provided in said nozzle for spinning into a filament.  
     
     
         9 . The melt spinning method according to  claim 7  wherein the biodegradable polymer material is heated in a supplying unit to a temperature lower than the melting temperature and is loaded into said melt mechanism for melting.  
     
     
         10 . The melt spinning method according to  claim 7  wherein said biodegradable polymer material is one of polylactic acid (PLA), polyglycolic acid (PGA), polyglactin (a polyglycolic acid-polylactic acid copolymer), polydioxanone, polyglyconate (a trimethylene carbonate-glycoid copolymer) and a polylactic acid-ε-caprolactone copolymer.