Apparatus and method for forming materials

Abstract

An apparatus and method for forming liquid spinning solution into a solid formed product. The liquid spinning solution is passed through a die assembly having a tubular passage having walls formed partly of semipermeable and/or porous material. In operation, draw down of the liquid spinning solution is performed partly within the die assembly. The semipermeable and/or porous material allows parameters, such as the concentration of hydrogen ions, water, salts and low molecular weight constituents, of the spinning solution to be altered as the spinning solution passes through the tubular passage.

1 . Apparatus for the formation of extruded materials from a solution, the apparatus comprising a die assembly that includes at least one extrusion orifice as an outlet from said die assembly for said extruded materials; wherein in operation draw down of the solution is performed at least partially within said die assembly.  
     
     
         2 . The apparatus according to  claim 1 , wherein in operation draw down of the solution is performed entirely within said die assembly.  
     
     
         3 . The apparatus according to  claim 1 , further comprising a dope reservoir connected to said die assembly, wherein said dope reservoir is capable of containing said solution and capable of supplying said solution to said die assembly.  
     
     
         4 . The apparatus according to  claim 3 , wherein said solution comprises a protein solution.  
     
     
         5 . The apparatus according to  claim 4 , wherein the protein of said protein solution is selected from the following group: 
 (a) recombinant spider silk proteins;    (b) analogs of recombinant spider silk proteins;    (c) recombinant silk-worm silk proteins;    (d) analogs of recombinant silk-worm silk proteins;    (e) regenerated silk solution from silk-worm silk; and    (f) mixtures of (a) to (e).    
     
     
         6 . The apparatus according to  claim 5 , wherein said protein solution is stored in said dope reservoir at a pH value above the isoelectric point of said protein.  
     
     
         7 . The apparatus according to  claim 1 , wherein said die assembly comprises at least one tubular passage, wherein said tubular passage delivers said solution to said extrusion orifice, and wherein in operation draw down of the solution commences within said tubular passage at a first distance from said extrusion orifice.  
     
     
         8 . The apparatus according to  claim 1 , wherein said die assembly comprises at least one tubular passage defined by one or more walls to form an internal surface, wherein said tubular passage delivers said solution to said extrusion orifice, and wherein in operation said solution detaches from said internal surface of said tubular passage at a second distance from said extrusion orifice.  
     
     
         9 . The apparatus according to  claim 8 , wherein in operation draw down of the solution commences within said tubular passage at a first distance from said extrusion orifice, and wherein said first distance is substantially equal to said second distance.  
     
     
         10 . The apparatus according to  claim 8 , wherein concentrically arranged feed means are positioned at an inlet end of said tubular passage to supply said solution and one or more additional components to the tubular passage.  
     
     
         11 . The apparatus according to  claim 8 , wherein a solvent-rich phase surrounds the extrusion and lubricates the region of the die assembly after detachment of said solution from said die assembly.  
     
     
         12 . The apparatus according to  claim 11 , wherein said solvent comprises water.  
     
     
         13 . The apparatus according to  claim 7 , wherein said tubular passage exhibits a tapered geometry for part or all of said passage, and wherein said tapered geometry is selected from the group consisting of: 
 (a) a divergent tapered geometry; and    (b) a convergent tapered geometry.    
     
     
         14 . The apparatus according to  claim 13 , wherein said tapered geometry is a substantially hyperbolic tapered geometry.  
     
     
         15 . The apparatus according to  claim 13 , wherein the region of the die assembly after the internal commencement of the tapered geometry is capable of being used to apply a coating to the extrusion.  
     
     
         16 . The apparatus according to  claim 13 , wherein the region of the die assembly after the internal commencement of the tapered geometry is capable of being used to apply a treatment to the extrusion.  
     
     
         17 . The apparatus according to  claim 7  wherein said tubular passage is defined by walls at least partly formed of material selected from the group of semipermeable materials and porous materials.  
     
     
         18 . The apparatus according to  claim 17 , wherein said material selected from the group of semipermeable materials and porous materials comprises a component selected from the group consisting of cellulose acetate based materials, cellulose acetate based materials substituted with diethylaminoethyl groups, cellulose acetate based materials substituted with carboxyl groups, and cellulose acetate based materials substituted with carboxymethyl groups.  
     
     
         19 . The apparatus according to  claim 17 , wherein said material selected from the group of semipermeable materials and porous materials comprises a hollow-fiber membrane selected from the group consisting of polysulfone membranes, polyethyleneoxide-polysulfone blend membranes, silicone membranes and polyacrylonitrile membranes.  
     
     
         20 . The apparatus according to  claim 17  wherein said tubular passage is defined by walls that are at least partly coated with a material selected from the following group: 
 (a) friction reducing material; and  
 (b) impermeable material.  
 
     
     
         21 . The apparatus according to  claim 17  wherein said walls are elastic.  
     
     
         22 . The apparatus according to  claim 17  wherein said tubular passage is defined by one or more walls formed at least partly of flexible material, wherein enclosure means surround said one or more walls to provide at least one pressurizable compartments surrounding said one or more walls, wherein the shape of said tubular passage can be controlled by pressurisation of said at least one pressurizable compartment.  
     
     
         23 . The apparatus according to  claim 22  wherein each of said at least one pressurizable compartment has a supply means for supplying fluent material to said at least one pressurizable compartment, and a removal means for removing fluent material from said at least one pressurizable compartment.  
     
     
         24 . The apparatus according to  claim 7 , wherein said tubular passage exhibits a substantially hyperbolic convergent tapered geometry, wherein said tubular passage is defined by one or more walls formed at least partly of a flexible elastic material, wherein enclosure means surround said one or more walls to provide one or more pressurisable compartments surrounding said one or more walls, wherein the shape of said tubular passage can be controlled by pressurisation of said at least one compartment, and wherein the region of the die assembly after the internal commencement of the tapered geometry is capable of being used to apply a treatment to the extrusion.  
     
     
         25 . The apparatus according to  claim 7  wherein said apparatus comprises a plurality of said tubular passages, each having an independent extrusion orifice and delivering said solution to the independent extrusion orifice.  
     
     
         26 . The apparatus according to  claim 22  wherein said die assembly has a plurality of said tubular passages, each having an independent extrusion orifice and delivering said solution to the independent extrusion orifice, all of said plurality of said tubular passages passing through each of said at least one pressurisable compartment.  
     
     
         27 . The apparatus according to  claim 1  wherein a plurality of said die assemblies is assembled together in a unit.  
     
     
         28 . The apparatus according to  claim 1  wherein said apparatus is incorporated into an electrospinning apparatus.  
     
     
         29 . A method of forming an extruded material from a solution using a die assembly, wherein at least part of a draw down process of said solution is performed within the die assembly.  
     
     
         30 . The method of  claim 29 , wherein all of said draw down process occurs within the die assembly.  
     
     
         31 . The method of  claim 29 , wherein said die assembly comprises at least one extrusion orifice as an outlet from said die assembly for said extruded material, wherein said die assembly further comprises at least one tubular passage within the die assembly that delivers said solution to said extrusion orifice, and wherein and at least part of said draw down process of said solution is performed within said tubular passage.  
     
     
         32 . The method of  claim 31 , wherein said extruded material is formed from a dope comprising a protein solution.  
     
     
         33 . The method of  claim 31 , wherein the protein of said protein solution is selected from the following group: 
 (a) recombinant spider silk proteins;    (b) analogues of recombinant spider silk proteins;    (c) recombinant silk-worm silk proteins;    (d) analogues of recombinant silk-worm silk proteins;    (e) regenerated silk solution from silk-worm silk; and    (f) mixtures of (a) to (e).    
     
     
         34 . The method of  claim 31 , wherein said tubular passage is defined by one or more walls formed at least partly of semipermeable and/or porous material and wherein said solution is treated, as it passes through said tubular passage to form the extrusion, by a component permeating through the semipermeable and/or porous material of said one or more walls.  
     
     
         35 . The method of  claim 34 , wherein said component is a fluid material.  
     
     
         36 . The method of  claim 34 , wherein at least two compartments surround said tubular passage, and different components are supplied to each of said compartments for treating said solution.  
     
     
         37 . The method of  claim 34  wherein said solution is treated with a treatment selected from the group consisting of diffusion, dialysis, reverse dialysis, ultrafiltration, electro-osmosis, pre-evaporation and a combination of these treatments.  
     
     
         38 . The method of  claim 37  wherein said solution comprises a phase separating mixture and wherein said components regulate a phase separation and polymerization process to produce filler particles or voids in the extruded material.  
     
     
         39 . The method of  claim 38 , wherein said solution is a dope comprising a protein solution, and wherein the protein of said protein solution is selected from the following group: 
 (a) recombinant spider silk proteins;    (b) analogues of recombinant spider silk proteins;    (c) recombinant silk-worm silk proteins;    (d) analogues of recombinant silk-worm silk proteins;    (e) regenerated silk solution from silk-worm silk; and    (f) mixtures of (a) to (e).    
     
     
         40 . The method of  claim 38  wherein at least two compartments surround said tubular passage, and different components are supplied to each of said compartments for treating said solution.  
     
     
         41 . The method of  claim 40 , wherein said solution is a dope comprising a protein solution, and wherein the protein of said protein solution is selected from the following group: 
 (a) recombinant spider silk proteins;    (b) analogues of recombinant spider silk proteins;    (c) recombinant silk-worm silk proteins;    (d) analogues of recombinant silk-worm silk proteins;    (e) regenerated silk solution from silk-worm silk; and    (f) mixtures of (a) to (e).