Kureha Kagaku Kogyo Kabushiki Kaisha

Kureha Chemical Industry Company, Limited

Naohiro Murayama

Teruo Sakagami

Toshiya Mizuno

Kenichi Nakamura

Noriyuki Arakawa

Makoto Fukuda

Hiroshi Obara

Yasufumi Fujii

Yoshikichi Teramoto

Shirou Suzuki

Masuhiro Shoji

Takayuki Katto

Yo Iizuka

Toshio Enoki

Yoshikazu Kokubu

Masafumi Yoshida

Shunzo Endo

Hideaki Doi

Masatomo Shigeta

Hiroyuki Fukuda

Teruo Fujii

Tadaaki Kato

Masayuki Funabashi

Shigeru Saitoh

Shoichiro Hayashi

Nobuhiro Moriyama

Masakazu Takaiwa

Katsuichi Machida

Haruko Kakutani

Tetuaki Kon

Masakatsu Wagu

Toru Hirai

Kiyomi Ohuchi

Tohshichi Kitago

Takayuki Katsuto

Sukiro Obata

Kenichi Kokubun

Syuji Terasaki

Takashi Ono

Yukihiro Shibuya

Masumi Sagi

Takao Oikawa

Sirou Sujuki

A polymer piezoelectric film comprising a poled film of a vinylidene fluoride copolymer having a high molecular weight as defined by an inherent viscosity within a specific range comprising 40 to 90 mol. % of vinylidene fluoride and 10 to 60 mol. % of trifluoroethylene. Such a high molecular weight vinylidene fluoride copolymer can give a preferable state of molecular arrangement during film formation, particularly preferably formation by casting, to provide a film excellent in piezoelectric characteristic and secondary processing characteristic.

Polymer piezoelectric film

Disclosed herein are an integrated carbon article of a large size having a bulk density of more than 1.01 g/cm.sup.3, comprising pieces of carbonaceous material(s) of the same or different quality and flexible graphite sheet(s) produced by interposing the flexible graphite sheet(s) between each of the pieces of carbonaceous material(s), bonding each of the pieces of carbonaceous material(s) and the flexible graphite sheet(s) with an adhesive agent and calcining the thus bonded material at a temperature of not lower than 800.degree. C.

Carbon article comprising pieces of carbonaceous material bonded with

A resin-made optical fiber is composed of a core of a polymer or copolymer obtained from a polymerizable monomer, which contains at least 1 wt. % of a crosslinkable monomer, and a cladding of a polymer of copolymer having a refractive index smaller than the core. The optical fiber is fabricated by filling a polymerizable monomer into a hollow fiber like cladding material, which is adapted to form a cladding and is made of a polymer or copolymer, and then placing the resultant composite material under polymerizing conditions to polymerize the polymerizable monomer. The latter step may preferably be carried out by causing the composite material to travel continuously in the direction of its length into a polymerization zone where conditions for the polymerization of the polymerizable monomer are satisfied, whereby the polymerizable monomer is successively polymerized to form a core having a refractive index greater than the cladding.

Optical fiber

A flexible carbon material is produced by carbonizing a composite material comprising carbon fibers having an average length of 6 to 50 mm and a binding agent. Carbon lumps are derived from the binding agent and are dispersed in a matrix of the carbon fibers so as to restrain a plurality of the carbon fibers while yet permitting relative slippage to occur as between the carbon fibers and carbon lumps such that the carbon fiber material exhibits a flexibility ratio D/d of not greater than 200 (where D is the diameter of curvature of the carbon material, when bent, just before breakage, and d is the thickness of the carbon material). The carbon fibers and lumps are preferrably present in an amount of from 5 to 50%, and 5 to 70% by volume, respectively, based upon the total volume of the carbon material.

Flexible carbon material

A photochromic lens is composed of a lens member made of a lens resin; and a photochromic layer applied on at least one side of the lens member and formed of a resin of a three-dimensional network structure. The layer-forming resin contains a spirooxazine compound represented by the following general formula (I): ##STR1## wherein R.sub.1 means a hydrogen or halogen atom or a cyano, C.sub.1-6 alkyl or C.sub.1-6 alkoxy group, and R.sub.2 denotes a C.sub.1-6 alkyl group, --CH.sub.2).sub.n COOH, --CH.sub.2).sub.n CN, substituted arylalkyl group or --CH.sub.2).sub.n COOR in which R is a C.sub.1-6 alkyl group and n stands for an integer of 1-4. The layer-forming resin may additionally contain a phenol resin and/or a phenolic compound. A hard coat layer may optionally be applied on the surface of the photochromic layer.

Photochromic lens

A vinylidene fluoride resin film having (1) a crystal melting point of 182.degree. C. or higher as measured by differential scanning calorimeter in nitrogen atmosphere at a temperature elevation speed of 10.degree. C./min; (2) a diffraction point corresponding to (1 1 .zeta.) of the .alpha.-phase crystal in the wide angle X-ray diffraction photograph; and (3) an orientation degree of the crystal of 0.85 or more when measured under irradiation of X-ray incident vertically on a major surface of the film. The vinylidene fluoride resin film is obtained by inflation accompanying melt necking stretching. The film has improved mechanical properties and heat-stability and is also adapted for use as a base film of a metallized film.

Vinylidene fluoride resin film and metallized film thereof

A halogen-containing resin lens material, having a refractive index of n.sub.D =1.55 or higher, an Abbe number of 27 or higher and good dyeable property and comprising a copolymer containing 10 to 90 wt. % of a monomer (I) represented by the formula (I) shown below: ##STR1## wherein: R.sup.1 represents hydrogen or CH.sub.3 group; X.sup.1 a halogen atom except for fluorin; and p the number of substituted halogens which is an integer selected from 1 to 5, and n is an integer selected from 1 to 4, R.sup.1 existing in plural number and being either identical or different, X.sup.1 when existing in plural number being either identical or different and 10 to 70 wt. % of a crosslinking monomer having two or more polymerizable functional groups (the percentages being based on the copolymer weight).

Halogen-containing resin lens material

A dielectric film is a stretched body of a composition comprising a thermoplastic resin cross-linked to have a gel content of about 10 to about 75%, and finely divided dielectric porcelain particles dispersed in the thermoplastic resin. Stretching does not result in a decrease in the dielectric constant of the film and provides a great electrostatic capacitance. The dielectric film is manufactured by a method comprising the steps of cross-linking the thermoplastic resin of the composition containing the dielectric porcelain particles as well, and stretching the composition at a predetermined temperature selected in association with the thermoplastic resin.

Dielectric films comprising stretched films of vinylidene fluoride and

Vinylidene fluoride polymer films are provided having improved dielectric constants and tan .delta. values and which do not exhibit substantial shrinkage when heated to temperatures below the crystalline melt point. Processes for preparation of such films are presented.

Dielectric film for capacitor and process for producing same

Disclosed herein is a thin transparent polytetrafluoroethylene film having:

Thin transparent polytetrafluoroethylene film and production process

Compositions each comprising a copolymer of a specific allylic or (meth)acrylic compound of an iodine-substituted benzoic acid derivative and a comonomer have a refractive index n.sub.D.sup.20 of at least 1.58 and an Abbe's number of at least 28 and are excellent starting materials for the production of high quality lenses.

Lens materials of high refractive indexes

Ultrafine fiber of an ethylene tetrafluoride copolymer having an orientation degree (.pi.) of at least 0.6 and an average fineness of 0.0001 to 0.9 denier. A process for producing such fiber or a porous membrane thereof is also disclosed.

Ultrafine fiber of an ethylene tetrafluoride copolymer and a process for

A transparent film of a vinylidene fluoride copolymer, comprising a dry film of a vinylidene fluoride copolymer having a parallel light transmittance of 85% or higher at a film thickness of 30 microns. The transparent film is obtained by forming a mixture of a vinylidene fluoride copolymer having a specifically high molecular weight with a solvent into a film, preferably by casting, and evaporating off the solvent.

Vinylidene fluoride copolymer film

A vinylidene fluoride resin having an inherent viscosity of 0.8 to 1.4 dl/g in dimethylformamide is melt-extruded and cooled and solidified under draft-stretching to form a film having a birefringence of 25.times.10.sup.-3 or larger. The film is heat-treated at 80.degree.-120.degree. C. and split into a split yarn. The split yarn has a Young's modulus even higher than that of the polypropylene split yarn and, when provided with a surface charge above the glass transition temperature, retains the charge semi-permanently. The charged split yarn is particularly suitable for forming a gas filter.

Vinylidene fluoride resin split yarn, process for production thereof and

A lens material having a refractive index n.sub.D.sup.20 of at least 1.57 or more and an Abbe's number .nu. of at least 30, comprising: a copolymer comprising (I) 10 to 85% by weight of a halogen-containing monomer represented by the following formula (1), (II) 15 to 90% by weight of a halogen-containing monomer represented by the following formula (2), and (III) 0 to 20% by weight of a monomer copolymerizable with the above mentioned monomers, the composition of the copolymer being based on the total quantity of the monomers (I), (II), and (III): ##STR1## wherein: D represents ##STR2## in which n represents an integer selected from the group consisting of 0, 1, and 2; each R.sup.1 represents hydrogen or a methyl group; Y represents CHOH; and r represents 0 or 1; each of X.sup.1 and X.sup.2 represents, independently from each other, a methyl group in which one through three of the hydrogen atoms are substituted by a member selected from the group consisting of bromine, iodine and a hydroxyl group (OH group), with the proviso that the number of substitution of the OH group is only one; X.sup.3 represents a methyl group in which one through three of the hydrogen atoms are substituted by a member selected from the group consisting of bromine, iodine and D, with the proviso that the number of substitution of D is only one; wherein at least one of X.sup.1, X.sup.2, and X.sup.3 contains at least one bromine or iodine; ##STR3## wherein: each R.sup.2 represents hydrogen or a methyl group; p represents an integer selected from the group consisting of 0, 1, 2, and 3; X.sup.4 represents bromine or iodine; and q represents an integer selected from the group consisting of 1, 2, 3, 4, and 5. An example of the copolymer is 1-methacryloxy-2,2-di(bromomethyl)-3-bromopropane/methacryloxypolyethyoxy- 2,4,6-tribromobenzene/styrene/divinylbenzene having a n.sub.D.sup.20 of 1.596 and a .nu. of 35.3.

Halogen-containing lens material

Growing community of inventors

Iwaki, Japan

Naohiro Murayama