Asahi Kasei Kogyo Kabushiki Kaisha

Yoshihiko Muto

Mitsuo Kohno

Kohei Watanabe

Yukinori Matsuoka

Tomoyuki Sakurai

Koichi Yasukata

A filter element comprising porous hollow fiber filter membranes arranged in a lengthwise direction and fusion-bonded together at one or both of their respective end portions to form a unified terminal block which has through-holes communicating with the hollows of the remaining unbonded portions of the membranes and having diameters substantially the same as the inner diameters of the membranes. The filter element not only is excellent in resistance to heat and chemicals, but also can realize an efficient filtration.

Hollow fiber membranes with fusion-bonded end portions

Disclosed is a biaxially drawn polyhexamethylene adipamide film having a relative viscosity of at least 3.2 as measured at 25.degree. C. in aqueous 96% H.sub.2 SO.sub.4, a degree of crystallinity of from 35% to 45%, a birefringence (.DELTA.n) of not more than 0.006, as determined at any point in its entire area, and an initial modulus of elasticity in tension of at least 230 kg/mm.sup.2 as determined in ay direction across substantially its entire area. The film may be produced by a process wherein molten polyhexamethylene adipamide is extruded through a circular die gap and the tubular extrudate is brought in sliding contact with the outer periphery of an inside mandrel, thereby to be cooled, which process is characterized in that polyhexamethylene adipamide having a relative viscosity of from 3.3 to 5.0, as measured at 25.degree. C. in aqueous 96% H.sub.2 SO.sub.4, is used; the tubular extrudate formed therefrom is cooled at a cooling rate (X.degree. C./sec.) satisfying the following formula with respect to the relative viscosity of the polymer used,

Biaxially drawn polyhexamethylene adipamide film and process for

Disclosed is a biaxially drawn polyhexamethylene adipamide film having a relative viscosity of at least 3.2 as measured at 25.degree. C. in aqueous 96% H.sub.2 SO.sub.4, a degree of crystallinity of from 35% to 45%, a birefringence (.DELTA.n) of not more than 0.006, as determined at any point in its entire area, and an initial modulus of elasticity in tension of at least 230 kg/mm.sup.2 as determined in any direction across substantially its entire area. The film may be produced by a process wherein molten polyhexamethylene adipamide is extruded through a circular die gap and the tubular extrudate is brought in sliding contact with the outer periphery of an inside mandrel, thereby to be cooled, which process is characterized in that polyhexamethylene adipamide having a relative viscosity of from 3.3 to 5.0, as measured at 25.degree. C. in aqueous 96% H.sub.2 SO.sub.4, is used; the tubular extrudate formed therefrom is cooled at a cooling rate (X.degree. C./sec.) satisfying the following formula with respect to the relative viscosity of the polymer used,

Growing community of inventors

Moriyama, Japan

Yoshihiko Muto