Method of producing a filament comprising a silica gel-fiber

1. A method of producing a filament comprising a silica gel fiber, comprising:

pressing a spinning composition containing the silica gel fiber through a nozzle plate comprising a number of nozzles in a range from 1 to 1000, each of the number of nozzles having a nozzle opening,

wherein the nozzle opening has a cross-sectional area of size A1,

wherein a tear-off edge with an angle β in a range from 5° to 90° extends around the nozzle opening,

wherein an area, which immediately adjoins the nozzle opening outside the nozzle and extends around the nozzle opening, has an area of the size A2,

wherein a ratio A2/A1 is not more than 1,

wherein the area of size A2 extends at an angle ω to the cross-sectional area of size A1,

wherein the angle ω is greater than 0° and less than 80°,

wherein each nozzle takes a form of a nozzle insert, which is inserted into a corresponding opening in the nozzle plate,

wherein each of the number of nozzles comprises a channel, the channel comprising a first cylindrical section extending vertically in the direction of flow, a second conical section to form a conical region, and a third cylindrical section extending vertically from the second conical section and forming a nozzle opening at an end distal from the second conical section;

wherein the conical region forms an angle γ with the third cylindrical section in the range of 10° to 80°

wherein the third cylindrical section has a length L and a diameter D;

wherein the following applies to a ratio L/D: 0.5≤L/D≤10; and,

wherein the entire conical region is disposed outside the plate.

2. The method of claim 1 , wherein the angle β of the tear-off edge is in a range from 10° to 90°.

3. The method of claim 1 , wherein the angle β of the tear-off edge is in a range from 20° to 90°.

4. The method of claim 1 , wherein the angle β of the tear-off edge is in a range from 30° to 90°.

5. The method of claim 1 , wherein the angle γ to the vertical in the range from 20° to 70°.

6. The method of claim 1 , wherein the angle γ to the vertical in the range from 30° to 60°.

7. The method of claim 1 , wherein the ratio L/D is in a range from 1 to 5.

8. The method of claim 1 , wherein the ratio L/D is in a range from 1.5 to 3.

9. The method of claim 1 , wherein the diameter D is 0.05 mm to 0.5 mm.

10. The method of claim 1 , wherein the diameter D is 0.1 mm to 0.3 mm.

11. The method of claim 1 , wherein the diameter D is 0.12 mm to 0.18 mm.

12. The method of claim 1 , wherein the cylinder adjoining the nozzle opening is disposed outside the plate.

13. The method of claim 1 , wherein the nozzle plate has a number of nozzles in a range from 4 to 100.