Spinnerette assembly for forming multicomponent hollow fibers

A spinnerette assembly for forming one or more multiple-sheath composite hollow fibers comprising:

• at least one extrusion orifice formed in said spinnerette assembly;
• a hollow needle extending through each said extrusion orifice in a concentric manner to define an annular passage around said needle in said extrusion orifice;
• a bore forming fluid passage communicating with the interior of each said needle;
• at least one core forming material passage formed in said spinnerette assembly, wherein each said core forming material passage comprises a core forming material inlet port extending from a surface of said assembly to an interior of said assembly and at least one transverse passage extending from said core forming material port to each said annular passage;
• and
• a first sheath forming material passage, wherein said first sheath forming material passage comprises a first sheath forming material port extending from a surface of said spinnerette assembly to each said annular passage
• a second sheath forming material passage, wherein said second sheath forming material passage comprises a second sheath forming material port extending from a surface of said spinnerette assembly to each said annular passage

A method for forming a composite hollow fiber comprising the steps of:

• delivering a core forming material to each annular passage in a spinnerette assembly, said core forming material entering said spinnerette assembly through one or more core forming material inlet ports and passing through the interior of said assembly to a transverse passage, a portion of said transverse passage entirely surrounding each needle in a continuous manner, and through an annular passage in communication with an extrusion orifice;
• delivering at least one sheath forming material concentrically around the core forming material as it traverses through each said annular passage;
• extruding the layered core forming material and at least one sheath forming material through the extrusion orifice and around each said needle, injecting a bore forming fluid into each needle to thereby provide a layered composite fiber comprising a bore forming fluid, a core forming material, and a sheath forming material as it exits the spinnerette assembly through the extrusion orifice;
• optionally passing the nascent extruded hollow fiber through an air gap;
• and
• solidifying the hollow fiber by cooling, solvent evaporation, or solvent extraction.