Kureha Kagaku Kogyo Kabushiki Kaisha

Hiroyuki Endoh

Tohru Sasaki

Kunizoh Kidoh

Seiichi Ohira

Hiroshi Ohhira

Seiichi Oohira

A vinylidene fluoride resin monofilament excellent in tensile strength and knot strength is further improved in abrasion resistance by heat-treating the oriented monofilament for such a short time period as to relax the orientation of only the surface portion of the monofilament. The vinylidene fluoride resin monofilament improved in abrasion resistance is characterized by a lower birefringence at the surface relative to a high average birefringence in a section perpendicular to the axis thereof.

Vinylidene fluoride resin monofilament and process for producing the same

A flexible monofilament of at least 0.08 mm in diameter excellent in transparency, high in impact strength and durability and showing a tensile strength of not less than 30 kg/mm.sup.2 and a modulus of elasticity of 60 to 120 kg/mm.sup.2, which is essentially composed of a vinylidene fluoride-based resin, a polymeric substance and a polyester plasticizer and is prepared by the process comprising the steps of:

Monofilament of improved vinylidene fluoride-based resin

A composite fiber comprises at least a two layer structure of a sheath and a core, each layer comprising a vinylidene fluoride resin, the core portion having an inherent viscosity of 1.10 dl/g and the sheath portion having an apparent viscosity lower than that of the core portion, said composite fiber having a birefringence of at least 36.0.times.10.sup.-3. This composite fiber, which has excellent knot strength (as high as 91 kg/mm.sup.2), high tensile strength (as high as 103 kg/mm.sup.2), excellent luster, and high processability and productivity, is produced by preparing a composite comprising a core portion of a vinylidene fluoride resin having an inherent viscosity of at least 1.10 dl/g and at least one layer of a sheath portion covering over said core portion, which has an apparent viscosity lower than that of the vinylidene fluoride resin of the core, while at least one of the core portion and the sheath portion is in molten state, and then subjecting the composite to at least one-step stretching to a stretching degree of 5.0-fold or more at a temperature which is lower by 5.degree. C. or more but not lower by 30.degree. C. or more than the melting point of the resin of the core.

Vinylidene fluoride resin filament and production thereof

The invention resides in a strong conjugate composite yarn highly adapted for use as a fishing line. The core material is a polyolefin having double refrax .DELTA.n amounting to at least 30.times.10.sup.-3. The sheath material is a polyamide or a polyester. The both core and sheath components are highly stretched and oriented.

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Iwaki, Japan

Hiroyuki Endoh