The present application discloses a method for preparing microporous PVA fiber comprising the following steps: Step 1: preparing spinning solution, calcium hydroxide solution, and sodium sulfate solution; Step 2: cooling the spinning solution to 40-60° C., and adding a foaming agent thereto to provide the PVA spinning stock solution; Step 3: spinning into the sodium sulfate solution so that the fiber containing the reaction product of the foaming agent and the mirabilite is dehydrated to provide a primary PVA fiber; Step 4: reacting the fiber with the calcium hydroxide solution to provide a secondary fiber; Step 5: foaming and pore forming; and Step 6: cleaning and drying to provide the final product of microporous PVA fiber.

The present application discloses a method for preparing microporous PVA fiber comprising the following steps: Step 1: preparing spinning solution, calcium hydroxide solution, and sodium sulfate solution; Step 2: cooling the spinning solution to 40-60° C., and adding a foaming agent thereto to provide the PVA spinning stock solution; Step 3: spinning into the sodium sulfate solution so that the fiber containing the reaction product of the foaming agent and the mirabilite is dehydrated to provide a primary PVA fiber; Step 4: reacting the fiber with the calcium hydroxide solution to provide a secondary fiber; Step 5: foaming and pore forming; and Step 6: cleaning and drying to provide the final product of microporous PVA fiber.

The present invention concerns methods for removing sulfur from yarn comprising the steps of: a) contacting never-dried polymeric yarn with an aqueous base, the polymer comprising imidazole groups and said polymer comprising sulfur atoms characterized as being in the form of sulfate anions; b) contacting the yarn with an aqueous acid solution of pH 5 or lower; and c) rinsing the yarn.

The present invention concerns methods for removing sulfur from yarn comprising the steps of: a) contacting never-dried polymeric yarn with an aqueous base, the polymer comprising imidazole groups and said polymer comprising sulfur atoms characterized as being in the form of sulfate anions; b) contacting the yarn with an aqueous acid solution of pH 5 or lower; and c) rinsing the yarn.

The invention relates to a process for the production of spunbonded nonwoven and a device for the production of spunbonded nonwoven, wherein, in the process, a spinning mass is extruded through a plurality of nozzle holes to form filaments, the filaments are drawn in the extrusion direction, precipitated at least partially by being subjected to a coagulation air stream comprising a coagulation liquid and deposited to form the spunbonded nonwoven. To establish a process which permits a cost-efficient and simple adjustment of the air permeability of the spunbonded nonwoven, it is suggested that the air permeability of the spunbonded nonwoven is adjusted on the basis of at least one parameter of the coagulation air stream in that the actual air permeability of the spunbonded nonwoven is measured, the difference between the actual air permeability and a predefined target air permeability is determined and the at least one parameter of the coagulation air stream is changed as a function of the determined difference.

The invention relates to a process for the production of spunbonded nonwoven and a device for the production of spunbonded nonwoven, wherein, in the process, a spinning mass is extruded through a plurality of nozzle holes to form filaments, the filaments are drawn in the extrusion direction, precipitated at least partially by being subjected to a coagulation air stream comprising a coagulation liquid and deposited to form the spunbonded nonwoven. To establish a process which permits a cost-efficient and simple adjustment of the air permeability of the spunbonded nonwoven, it is suggested that the air permeability of the spunbonded nonwoven is adjusted on the basis of at least one parameter of the coagulation air stream in that the actual air permeability of the spunbonded nonwoven is measured, the difference between the actual air permeability and a predefined target air permeability is determined and the at least one parameter of the coagulation air stream is changed as a function of the determined difference.

A spinning nozzle which has a perforated part in which ejection holes have been arranged in a density as high as 600-1,200 holes/mm.sup.2. This process for producing a fibrous bundle comprises ejecting a spinning dope having a viscosity as measured at 50° C. of 30-200 P from the ejection holes of the spinning nozzle to produce a fibrous bundle. This fibrous bundle has a single-fiber fineness of 0.005-0.01 dtex. By the wet-process direct spinning, a mass of nanofibers which are stably uniform and continuous can be produced at a high efficiency.

This invention relates to a process and a device for manufacturing cellulose-based webs which are directly formed from lyocell spinning solution and in particular for the washing of directly formed cellulose webs.

This invention relates to a process and a device for manufacturing cellulose-based webs which are directly formed from lyocell spinning solution and in particular for the washing of directly formed cellulose webs.

Fibrous structures and more particularly to fibrous structures that exhibit improved TEWL properties, for example lower TEWL % Difference Values as measured according to the TEWL Test Method described herein, compared to known fibrous structures, sanitary tissue products comprising such fibrous structures and method for making such fibrous structures are provided.