Provided are staple fibers for air laid capable of improving dispersibility, and a method for producing the same. The staple fibers for air laid are characterized by including stable fibers to which a fiber treatment agent containing a hydrophilic oil agent and a silicone-containing oil agent is adhered in an amount of 0.7 to 2 wt % of a weight of the staple fibers, wherein a weight ratio of the hydrophilic oil agent and the silicone-containing oil agent contained in the fiber treatment agent (a weight of the hydrophilic oil agent/a weight of the silicone-containing oil agent) is within a range of 60/40 to 90/10, and a moisture content is 2 to 13%.

Provided are staple fibers for air laid capable of improving dispersibility, and a method for producing the same. The staple fibers for air laid are characterized by including stable fibers to which a fiber treatment agent containing a hydrophilic oil agent and a silicone-containing oil agent is adhered in an amount of 0.7 to 2 wt % of a weight of the staple fibers, wherein a weight ratio of the hydrophilic oil agent and the silicone-containing oil agent contained in the fiber treatment agent (a weight of the hydrophilic oil agent/a weight of the silicone-containing oil agent) is within a range of 60/40 to 90/10, and a moisture content is 2 to 13%.

Provided is a composition for the treatment of fibers, such as PAN precursor fibers. The finish composition includes a polysiloxane; an emulsifier; water; and a dicarboxylic acid having a pK.sub.a from 1 to 4, and boiling point from 200 to 400° C. The dicarboxylic acid may have the following formula: ##STR00001##
where R.sub.1 is absent or a saturated or unsaturated, linear or branched, aromatic substituted or unsubstituted, hydrocarbon group; Y.sub.1 and Y.sub.2 are independently hydrogen, nitrogen, oxygen, sulfur, phosphorus, C.sub.1-C.sub.6 alkyl group, or an alkoxy group; and X.sub.1 and X.sub.2 are independently one or more hydrogen atoms, a metal, a quaternary amine, or a hydrocarbon group having up to 6 carbon atoms, the hydrocarbon group being an alkyl group, an alkylene group, or an aromatic group, which may be branched or linear, and may optionally have one or more heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur and phosphorus.

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.

Disclosed herein are a novel crown ether with bulky and rigid groups and a method for preparing the same. Also provided are a lithium adsorbent comprising the novel crown ether immobilized onto a nanofiber, and a method for preparing the same. The lithium-selective crown ether is synthesized through intermolecular cyclization between a bulky epoxide and a rigid aromatic compound such as 1,2-dihydroxybenzene, and can effectively recover lithium ions. For use as a lithium adsorbent, the novel crown ether with both bulky and rigid subunits is immobilized onto a polymer nanofiber. The crown ether-immobilized polymer nanofibers may be formed into a recyclable membrane.

Disclosed herein are a novel crown ether with bulky and rigid groups and a method for preparing the same. Also provided are a lithium adsorbent comprising the novel crown ether immobilized onto a nanofiber, and a method for preparing the same. The lithium-selective crown ether is synthesized through intermolecular cyclization between a bulky epoxide and a rigid aromatic compound such as 1,2-dihydroxybenzene, and can effectively recover lithium ions. For use as a lithium adsorbent, the novel crown ether with both bulky and rigid subunits is immobilized onto a polymer nanofiber. The crown ether-immobilized polymer nanofibers may be formed into a recyclable membrane.

Provided is a method for manufacturing a protection board. A reinforcement fabric including multiple reinforcement fibers is provided, each reinforcement fiber containing multiple adjacent filaments, each filament being composed of a core and a shell formed around the core, and a melting temperature of the shell is lower than a melting temperature of the core, the shell of each filament attached to the shell of the adjacent filament. The impact strength of the shell is higher than the impact strength of the core. The reinforcement fabric can be manufactured into a protection board with good impact resistance simply through heating and molding. Therefore, the reinforcement fabric has the advantage of both manufacturing a protection board with good impact resistance and reducing its process complexity and cost.

Provided is a method for manufacturing a protection board. A reinforcement fabric including multiple reinforcement fibers is provided, each reinforcement fiber containing multiple adjacent filaments, each filament being composed of a core and a shell formed around the core, and a melting temperature of the shell is lower than a melting temperature of the core, the shell of each filament attached to the shell of the adjacent filament. The impact strength of the shell is higher than the impact strength of the core. The reinforcement fabric can be manufactured into a protection board with good impact resistance simply through heating and molding. Therefore, the reinforcement fabric has the advantage of both manufacturing a protection board with good impact resistance and reducing its process complexity and cost.

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.