Spinning apparatus providing for essentially constant extensional strain rate

Claim 2

In apparatus for spinning filaments from fiber-forming, liquid polymeric material which apparatus includes a spinneret for extending said material through at least one converging nozzle passagway having an entry opening, and an exit orifice with a cross-sectional area in the range of about 3 × 10 - 6 to 50 × 10 - 4 square centimeters, the improvement wherein said nozzle passageway is bounded by gradually curving walls having a profile shaped to provide an essentially constant extensional strain rate on liquid polymeric material extruded therethrough to form a filament solely of that material, said profile being described essentially by the equation ##EQU9## where: R is the perpendicular distance between an axis of the passageway axis and the nozzle wall at the exit orifice; r w is the perpendicular distance between nozzle wall and point along that axis; Z is the distance along that axis measured from said exit orifice; and A is a constant.

Claim 3

The apparatus according to claim 1 wherein said profile is defined by a surface of revolution defined by a generatrix described by said equation and moving about said axis in a generally circular path.

Claim 4

The apparatus according to claim 2 wherein the constant A in said equation is defined by ##EQU10## where θ is the conical half angle of an equivalent frustoconical passageway for establishing a maximum extensional strain rate essentially equal to said essentially constant extensional strain rate.

Claim 5

The apparatus according to claim 1 wherein said passageway is contiguous with and tangent to the walls of a frusto-conical passageway.

Claim 6

The apparatus according to claim 4 wherein the angle of intersection between the axis of said converging passageway and said walls of said passageway is between about 15° to 45°.

Claim 7

The apparatus according to claim 1 wherein the length of said passageway is in the range of about 0.020 to 0.060 inches.

Claim 8

The apparatus according to claim 1 wherein the length of said passageway is in the range of about 0.1 to 0.6 inches.

Claim 9

The apparatus according to claim 1 wherein the cross-sectional area of the exit orifice of said passageway is in the range of about 3 × 10 - 6 to 50 × 10 - 6 square centimeters.

Claim 10

The apparatus according to claim 1 wherein the cross-sectional area of the exit orifice of said passageway is in the range of about 1 × 10 - 4 to 50 × 10 - 4 square centimeters.

Claim 11

The apparatus according to claim 1 wherein the length of said passageway is in the range of about 0.020 to 0.060 inches and wherein the cross-sectional area of the exit orifice of said passageway is in the range of about 3 × 10 - 6 to 50 × 10 - 6 square centimeters.

Claim 12

The apparatus according to claim 1 wherein the length of said passageway is in the range of about 0.1 to 0.6 inches and wherein the cross-sectional area of the exit orifice of said passageway is in the range of about 1 × 10 - 4 to 50 × 10 - 4 square centimeters.

Claim 13

The apparatus according to claim 1 wherein the length of nozzle passageway is in the range of about 0.020 to 0.6 inches.

Claim 14

Apparatus for forming yarn from liquid polymeric material comprising: a spinneret for extruding the material through a plurality of converging nozzle passageways each having an entry opening, and an exit orifice with a cross-sectional area in the range of about 3 × 10 - 6 to 50 × 10 - 4 square centimeters; each passageway being bounded by gradually curving walls having a profile shaped to provide essentially constant extensional strain rate on liquid polymeric material extruded therethrough to form a filament solely of that material, said profile being described essentially by the equation ##EQU11## where: R is the perpendicular distance between an axis of the passageway and the nozzle wall at the exit orifice; r w is the perpendicular distance between the nozzle wall and points along that axis; Z is the distance along that axis measured from said exit orifice; and A is a constant; a guide roll; and draws rolls for pulling filaments from a plurality of the nozzles of the spinneret over said guide roll as yarn.

Claim 15

Apparatus for forming yarn from liquid polymeric material comprising: a spinneret for extruding the material through a plurality of converging nozzle passageways each having an entry opening, and an exit orifice with a cross-sectional area in the range of about 3 × 10 - 6 to 50 × 10 - 4 square centimeters; each passageway being bounded by gradually curving walls having a profile shaped to provide essentially constant extensional strain rate on liquid polymeric material extruded therethrough to form a filament solely of that material, said profile being described essentially by the equation ##EQU11## where: R is the perpendicular distance between an axis of the passageway and the nozzle wall at the exit orifice; r w is the perpendicular distance between the nozzle wall and points along that axis; Z is the distance along that axis measured from said exit orifice; and A is a constant; a guide roll; and draws rolls for pulling filaments from a plurality of the nozzles of the spinneret over said guide roll as yarn.