Method and apparatus for improved extrusion of essentially inviscid jets

Claim 1

An improved orifice assembly for the formation of fibers and filaments from an essentially inviscid melt by extrusion thereof through an orifice in an extrusion orifice plate as a free molten filamentary stream in a film-forming atmosphere whereby the stream is maintained in filamentary form by a film until solidified, the improvement comprising a. a second plate positioned beneath said orifice plate and having an orifice substantially coaxial with said extrusion orifice, said orifice plate and second plate defining an enclosed chamber having a gap distance therebetween in the vicinity of said orifices less than one-half the diameter of said second plate orifice, said second plate orifice further having a length less than 100 times the diameter of said extrusion plate orifice and a diameter less than 30 times the diameter of said extrusion plate orifice; and b. port means communicating with said enclosed chamber for providing a predetermined flow of inert gas from said port means into said second plate orifice thereby providing a blanket of inert gas about the molten stream as it passes through said enclosed chamber and said second plate orifice into the film forming atmosphere.