A polyvinyl alcohol fiber that is excellent in water absorption properties, water solubility and mechanical strength; a fiber structure including the polyvinyl alcohol fiber; and a method for producing the polyvinyl alcohol fiber are provided. The polyvinyl alcohol fiber includes 1 mol % or more of at least one functional group selected from a sulfonic acid group, a sulfonate group, a maleic acid group, an itaconic acid group, an acrylic acid group, and a methacrylic acid group. The polyvinyl alcohol fiber has a degree of cross-linking of 0% and a tensile strength of 3 cN/dtex or more.

Fibrous elements containing one or more fibrous element-forming materials and one or more polyethylene oxides, and methods for making same are provided.

Fibrous elements containing one or more fibrous element-forming materials and one or more polyethylene oxides, and methods for making same are provided.

Provided is a fibrous adsorbing material used for the adsorption and recovery of metals in a solution, which is a fibrous metal-adsorbing material that can be produced using existing production facilities without using special facilities or complicated operations, has high durability, is easy to diversify, and can be processed into various forms. The fibrous metal-adsorbing material is produced by a) a step of preparing an acrylate polymer having a large number of glycidyl groups in the molecule, b) a step of kneading a low-melting-point fiber matrix polymer therewith, c) a step of making the resulting mixture into a fibrous form by an melt-blend spinning method, and d) a step of allowing a long-chain ligand having an amino group or an imino group to react with glycidyl groups on the fiber surface to introduce a metal-adsorbing functional group. The fibrous metal-adsorbing material has high durability, is easy to diversify, and has various forms.

Provided is a fibrous adsorbing material used for the adsorption and recovery of metals in a solution, which is a fibrous metal-adsorbing material that can be produced using existing production facilities without using special facilities or complicated operations, has high durability, is easy to diversify, and can be processed into various forms. The fibrous metal-adsorbing material is produced by a) a step of preparing an acrylate polymer having a large number of glycidyl groups in the molecule, b) a step of kneading a low-melting-point fiber matrix polymer therewith, c) a step of making the resulting mixture into a fibrous form by an melt-blend spinning method, and d) a step of allowing a long-chain ligand having an amino group or an imino group to react with glycidyl groups on the fiber surface to introduce a metal-adsorbing functional group. The fibrous metal-adsorbing material has high durability, is easy to diversify, and has various forms.

[Problem to be solved] a polyvinyl alcohol fiber that have sufficient shrinkage rate and shrinkage stress when absorbing moisture at a temperature equal to room temperature or higher, especially around 35 C. is provided.

[Solution] the present invention relates to a polyvinyl alcohol fiber containing modified polyvinyl alcohol containing 1 mol % or more of a carboxyl group and having a birefringence index of 0.040 or more, a fiber structure using the polyvinyl alcohol fiber, and a method for producing the polyvinyl alcohol fiber.

[Problem to be solved] a polyvinyl alcohol fiber that have sufficient shrinkage rate and shrinkage stress when absorbing moisture at a temperature equal to room temperature or higher, especially around 35 C. is provided.

[Solution] the present invention relates to a polyvinyl alcohol fiber containing modified polyvinyl alcohol containing 1 mol % or more of a carboxyl group and having a birefringence index of 0.040 or more, a fiber structure using the polyvinyl alcohol fiber, and a method for producing the polyvinyl alcohol fiber.