Kureha Kagaku Kogyo Kabushiki Kaisha

Tohru Sasaki

Syuuzi Terasaki

Hiroyuki Endoh

Shinsuke Yoshikawa

Takao Ichii

Tomoo Susa

Mitsuru Ohta

Shuji Terasaki

Hiroshi Ohhira

Hiroyuki Endo

Kunizoh Kidoh

Seiichi Ohira

Masafumi Yoshida

Hideo Munakata

Syozo Kakizaki

Seiichi Oohira

Mutsuru Ohta

Hirosi Ohhira

Shozo Kakizaki

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 dielectric film contains from 40 to 97% by volume of a thermoplastic resin, from 2 to 50% by volume of a ceramic dielectric and from 1 to 25% by volume of carbon black. The composite film contain a base film layer composed of said dielectric film and the dielectric film of the thermoplastic resin provided on at least one surface thereof.

Dielectric films and process for preparing same

The capacitor contains a film layer comprising essentially a vinylidene fluoride resin and a coating layer composed of a mixture of the vinylidene fluoride resin and a polymer substantially incompatible with the vinylidene fluoride resin and having a critical surface tension of 30 dyn/cm or higher. The capacitor components as set forth hereinabove can render the capacitor compact without decreasing the performance inherent in the polyvinyl fluoride resin.

Capacitor

A film prepared by molding a resin compound of a polyvinylidene fluoride admixed with a polycarbonate and/or a thermoplastic polyester and stretching into at least one direction is disclosed. The film shows excellent dielectric properties.

Dielectric film

Capacitor having layers of dielectric material containing at least one oriented film prepared by molding a resin composition comprising polyvinylidene fluoride, polycarbonate and/or thermoplastic polyester into un-stretched film and stretching the thus molded un-stretched film as at least a part of the constituents of the layer of dielectric material is disclosed.

The invention provides improved composite and conjugate filaments to be used exclusively in in-water submerged purposes. Each of these filaments consists of a core of vinylidene fluoride resin consisting in turn of one or more filamentary element(s), while a sheath consists of polyamide resin. The composing ratio as measured between the cross-sections of these both resins is defined by a value extending from 1/99-to 40/60, preferably from 3/97 to 30/70, still more preferably between 3/97 and 20/80.

Composite and conjugate filaments

An improved polyvinylidene fluoride resin-made filament. It consists substantially of a blend of 99-wt. % of a first polyvinylidene fluoride resin component having an inherent viscosity higher than 1.30 dl/g on the one hand, and 1-60 wt. % of a second polyvinylidene fluoride component having an inherent viscosity lower than 1.20 dl/g on the other. The blend has a critical shearing stress lower than 2.8.times.10 dyne/cm.sup.2 and is subjected to melt-spinning and successively to a primary and a secondary stretching in a temperature region of 70.degree.-180.degree. C. The overall stretch factor is selected to be 4-10.

Polyvinylidene fluoride filaments

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.

Concentric composite conjugate yarns and a process for manufacturing same

A piezoelectric and pyroelectric film made from a resin composition of polymer of vinylidene fluoride, which is characterized by an index of birefringence of larger than 3.times.10.sup.-3 and a ratio of d.sub.31 /d.sub.32 of 0.3 to 3.0, and which may be prepared by further stretching a biaxially stretched film made from the above-mentioned resin composition at a temperature lower than the temperature of the biaxially stretching by more than 20.degree. C. before or at the same time of a treatment for orientation polarization of the film.

Piezoelectric and pyroelectric film and method for preparing the film

A method and laminate for protecting an article from exposure to radiant heat are disclosed. The laminate is formed by adhering a metal coating to one surface of a polymeric film of polyfluoroolefin or fluoroolefin copolymer, having not more than a 50% transmission ratio of visible ray and not less than a 30% transmission ratio of infrared ray. The laminate is adhered to a surface of the article to be protected with the polymeric surface outward.

Heat-insulation material

Separate polarizing electrodes are attached to the opposite surfaces of a thermoplastic film. A high D. C. voltage is then applied across these electrodes to polarize the film to produce an electric element, such as an electret, piezoelectric or pyroelectric element. Portions of the polarizing electrodes are then selectively removed to form the operating electrodes required for the electric element.

Method for producing thermoplastic film electric element

Metallized plastic films having deposited metal layers on both surfaces and being adapted for use as dielectric films, piezoelectric films or pyroelectric films are disclosed. At least a portion of the metal layer deposited on one surface of the film has a relatively increased thickness of 700 A or more and at least a portion of the metal layer deposited on the other surface has a relatively reduced thickness of 600 A or less. The increased thickness and reduced thickness portions are positioned opposite to one another. The thin layer permits rapid self recovery of localized dielectric breakdown, while the relatively thick layer provides better utility for the electric uses to which the film is put.

Metallized film

A method is disclosed for polarizing a thermoplastic resin film having a continuous metal electrode on one surface and a plurality of discrete electrodes on the other surface. An additional thermoplastic resin film coated on one surface with an evaporated metal coating is placed on the first thermoplastic resin film such that the evaporated metal coating comes into contact with the discrete electrodes. A polarizing d.c. voltage is applied between the continuous metal electrode and the evaporated metal coating.

Growing community of inventors

Iwaki, Japan

Tohru Sasaki