Infrared solvent stripping process

1. A process for stripping chemically bonded spinning solvent from a solution-spun nonwoven web comprising the steps of:

providing a nonwoven web comprising solvent-laden polymeric fibers having average fiber diameters of less than about 1 micrometer,

transporting the nonwoven web through a first zone in which a solvent stripping fluid impinges on the nonwoven web in order to reduce the solvent concentration of the fibers to less than about 10,000 ppmw, and

transporting the nonwoven web through a second zone wherein infrared radiation irradiates the nonwoven web and the bound solvent concentration is reduced to less than about 1000 ppmw.

2. The process according to claim 1 wherein the average fiber diameter is less than 0.8 micrometer.

3. The process according to claim 2 , wherein the average fiber diameter is less than 0.5 micrometer.

4. The process according to claim 1 , wherein the solvent stripping fluid is heated.

5. The process according to claim 4 , wherein the solvent stripping fluid is heated to between about 70° C. and the melting point of the fiber polymer.

6. The process according to claim 4 , wherein the solvent stripping fluid is heated to between about 70° C. and the decomposition point of the fiber polymer.

7. The process according to claim 1 , wherein the solvent stripping fluid is selected from the group of air, nitrogen, argon, helium, carbon dioxide, hydrocarbons, halocarbons, halohydrocarbons, and mixtures thereof.

8. The process according to claim 7 , wherein the solvent stripping fluid is air.

9. The process according to claim 1 , wherein the bound solvent concentration is reduced to less than 300 ppmw.

10. The process according to claim 1 , further comprising transporting the web through the solvent stripping zone by pinning the nonwoven web to a moving porous belt with a vacuum source located on the side of the porous belt opposite the nonwoven web, and passing fresh solvent stripping fluid through the web.

11. The process according to claim 1 , wherein the nonwoven web is transported through the solvent stripping zone on top of a scrim.

12. The process according to claim 1 , further comprising transporting the nonwoven web through at least one additional solvent stripping zone.

13. The process according to claim 12 , wherein the at least one additional solvent stripping zone wherein a solvent stripping fluid heated to at least about 70° C. impinges on the nonwoven web.

14. The process according to claim 13 , wherein the nonwoven web is transported through the at least one additional solvent stripping zone prior to the solvent stripping zone which includes the infrared radiation.