Kureha Corporation

Shingo Taniguchi

Takeo Takahashi

Yasuhiro Tada

Masayuki Hino

Kenichi Suzuki

Toshiya Mizuno

Satoshi Hashimoto

Masaru Satou

Hiroshi Sakabe

Kazuhiko Sunagawa

Yui Yoshida

Disclosed are a branched poly(arylene sulfide) resin having a melt viscosity measured at a temperature of 310&#xb0; C. and a shear rate of 1200 secof 65 to 450 Pa&#xb7;s, a maximum draft ratio of 6500 or more, and a degree of whiteness of 65 or more; moreover, a branched poly(arylene sulfide) resin preferably having a dependence of melt viscosity on shear rate of 1.4 to 2.6 or a melt stability of 0.85 to 1.30; and a method for producing a branched poly(arylene sulfide) resin, wherein a sulfur source and a dihaloaromatic compound are caused to undergo a polymerization reaction at a temperature of 170 to 290&#xb0; C. in the organic amide solvent in the presence of a polyhaloaromatic compound in an amount of 0.0001 to 0.01 mol per mol of the fed sulfur source.

Branched poly(arylene sulfide) resin and method for producing same

A composition is formed by blending a vinylidene fluoride resin having a relatively high molecular weight and an improved crystallinity represented by a difference Tm&#x2212;Tc of at most 32&#xb0; C. between an inherent melting point Tmand a crystallization temperature Tc of the resin with a plasticizer and a good solvent for vinylidene fluoride resin, and the composition is melt-extruded into a hollow fiber-form. The hollow fiber-form extrudate is then cooled to be solidified from an outside thereof by introduction into cooling medium and subjected to extraction of the plasticizer and stretching, thereby forming a hollow fiber porous membrane of vinylidene fluoride resin characterized by co-presence of crystal oriented portion and crystal non-oriented portion recognizable by X-ray diffraction method. The resultant hollow fiber porous membrane of vinylidene fluoride resin has micro-pores of appropriate size and distribution, is excellent in mechanical strength represented by tensile strength and elongation at break and is useful as a water microfiltration membrane.

Porous water filtration membrane of vinylidene fluoride resin hollow fiber and process for production thereof

Monofilaments comprising resin compositions which contain 1% by mass or more of a comonomer component (for example, hexafluoropropylene), have an intrinsic viscosity of 1.3 dl/g or more and a melting point of 165&#xb0; C. or higher and contain a PVDF-based resin. Owing to the above composition and physical properties, the crystallinity and elastic modulus of the PVDF-based resin are altered. As a result, an appropriate flexibility can be imparted to the monofilaments while preventing deterioration in the mechanical properties.

Resin compositions, monofilaments, process for producing the same and fishing lines

A vinylidene fluoride resin having a weight-average molecular weight as relatively high as 300,000 or higher is mixed with a plasticizer and good solvent for the vinylidene fluoride resin to obtain a composition. A molten extrudate of the composition in a hollow-fiber membrane state is contacted, on its outer side, with a cooling liquid inert to the vinylidene fluoride resin to thereby cool the extrudate. During the solidification, the vinylidene fluoride resin is moderately and mildly crystallized. Thus, a hollow-fiber porous vinylidene fluoride resin membrane is produced which has a high crystallinity represented by an enthalpy of crystal melting 58 J/g or higher. The hollow-fiber porous membrane obtained is excellent in mechanical strength represented by tensile strength and elongation at break and in chemical resistance. It is effectively used as a water microfiltration membrane.

Hollow-fiber porous water filtration membrane of vinylidene fluoride resin and process for producing the same

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Fukushima-ken, Japan

Shingo Taniguchi