Electroblowing web formation
View Patent ↗An improved electroblowing process is provided for forming a fibrous web of nanofibers wherein polymer stream is issued from a spinning nozzle in a spinneret with the aid of a forwarding gas stream, passes an electrode and a resulting nanofiber web is collected on a collector. The process includes applying a high voltage to the electrode and grounding the spinneret such that an electric field is generated between the spinneret and the electrode of sufficient strength to impart an electrical charge on the polymer as it issues from the spinning nozzle.
1. A fiber spinning apparatus, comprising:
a polymer supply vessel connected to an inlet side of a spinneret having a polymer flow passage disposed therein, said polymer flow passage exiting said spinneret through at least one spinning nozzle; forwarding gas nozzles having exits disposed adjacent to and directed toward said spinning nozzle, said spinning nozzle extending beyond the exits of said gas nozzles; at least one electrode disposed downstream of said gas nozzles, but outside of a gas flow path established by the direction of the gas flow nozzles; and a fiber collector disposed downstream of said spinning nozzle, wherein each of said electrode and said fiber collector are electrically connected to a circuit containing a high voltage supply, such that each can be individually charged to a potential, and the spinneret is grounded, and the spinning nozzle has a tip, said tip having an angular geometry such that an electric field is caused between the tip and the electrode.
2. The fiber spinning apparatus of claim 1 , wherein said polymer supply vessel is a storage tank for a polymer solution.
3. The fiber spinning apparatus of claim 1 , wherein said polymer supply vessel is a melt extruder for a polymer melt.
4. The fiber spinning apparatus of claim 1 , wherein said gas nozzles are circumferential slots surrounding said spinning nozzle.
5. The fiber spinning apparatus of claim 1 , wherein said spinneret is a beam having a linear capillary array of spinning nozzles contained therein each having an angular tip and polymer flow passage defined therein, with said polymer flow passage exiting said spinneret at said angular tip of each spinning nozzle, said forwarding gas nozzles are slots running along the length of said linear array, formed between said angular tip and elongated knife edges disposed on either side of said angular tip, and said electrode comprises two bars running the length of said spinneret.