Spinneret, method of heating a spinneret and lyocell process
A method of producing lyocell filaments employs a steam heatable spinneret having a rectangular shape with an aspect ratio of more than 2 and comprising at least a top housing and a nozzle frame. The spinneret is heated and used for spinning cellulosic filaments from a cellulose solution in a solvent. A lyocell process employs the spinneret.
1. A method of producing lyocell filaments; employing a steam heatable spinneret having a rectangular shape with an aspect ratio of more than 2 and comprising at least a top housing and a nozzle frame, the method comprising:
preparing a spinning solution and extruding the spinning solution with the steam heatable spinneret,
wherein the top housing or the top housing and the nozzle frame is heated by steam having a temperature ranging from 105 to 138° C. and a pressure ranging from 1.2 to 4 bar.
2. The method according to claim 1 , wherein the steam heatable spinneret further comprises individual nozzle plates within the nozzle frame.
3. The method according to claim 1 , wherein the top housing and the nozzle frame are heated by steam.
4. The method according to claim 1 , wherein the steam heatable spinneret is further heated by additional heating that is different from heating by steam.
5. The method according to claim 1 , wherein the steam heatable spinneret has an aspect ratio of from 5 to 25.
6. The method according to claim 1 , wherein the top housing or the top housing and the nozzle frame is heated by steam having a temperature ranging from 110 to 130° C. and a pressure ranging from 1.5 to 3.4 bar.
7. The method according to claim 1 , wherein the top housing and the nozzle frame are made of stainless steel.
8. The method according to claim 1 , wherein the steam heatable spinneret further comprises a breaker.
9. The method according to claim 8 , wherein the breaker is steam heatable.
10. The method according to claim 1 , wherein the steam heatable spinneret is a multi-nozzle plate spinneret, wherein the nozzle frame comprises lands which are steam heatable.