Nok Corporation

Yutaka Koda

Takao Kanno

Hirokazu Yamamoto

Hirokazu Nagato

Yusuke Ikawa

Yoshihide Takahashi

Tamio Inamura

Disclosed is a method for producing a hollow fiber carbon membrane using a hollow fiber carbon membrane-forming material by means of a dry method or dry-wet method comprising a spinning step, a drying step, an infusibilization step, and a carbonization step as basic steps; wherein in the infusibilization step, heat treatment is performed at least two times at different temperatures, with the second temperature being higher than the first temperature. It is preferable that the second heat treatment is performed directly after the first treatment is performed, without once cooling to room temperature. The obtained hollow fiber carbon membrane has improved permeability, without reducing its separation coefficient.

Method for producing hollow fiber carbon membrane

A hollow fiber membrane module comprising a bundling tube including a body part and head parts placed at both terminals of the body part and O-rings with which the bundling tube is fitted into a housing being attached to outer circumferential surfaces of the head parts, wherein at least one of the head parts are divided into two in a place closer to a terminal of the bundling tube than places where the O-rings are attached while maintaining a cylindrical shape of the head part, and the divided parts have a slidable structure while maintaining a coupled condition therebetween that forms the cylindrical shape. The hollow fiber membrane module is capable of preventing damage effectively on a hollow fiber membrane or the bundling tube due to expansion or contraction of the hollow fiber membrane to be caused by change of an external environment such as temperature.

Hollow fiber membrane module

A magnetic fluid containing fine particles of ferrite stably dispersed in a carrier liquid is prepared by adding carrier liquid and a dispersing agent selected from N-polyalkylenepolyamine-substituted alkenylsuccinimide, an oxyalkylene-substituted phosphoric acid ester and a nonionic surfactant, and, if required, hydrocarbon solvent having a low boiling point to particles of ferrite which is coated with water-soluble surfactant and subjecting the resulting mixture to a dispersion treatment and, if required, removal of the hydrocarbon solvent.

Process for preparing a magnetic fluid

A magnetic fluid containing fine particles of ferrite stably dispersed in a low vapor pressure base oil is prepared by adding N-polyalkylenepolyamine-substituted alkenylsuccinimide (and a low vapor pressure base oil) to a suspension of fine particles of surfactant-adsorbed ferrite dispersed in a low boiling point hydrocarbon solvent, heating the resulting mixture, separating the hydrocarbon solvent therefrom, adding a low vapor pressure base oil and a specific dispersing agent to the fine particles of N-polyalkylenepolyamine-substituted alkenylsuccinimide-coated ferrite as the residues and subjecting the resulting mixture to a dispersion treatment.

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Shizuoka, Japan

Yutaka Koda