Central Glass Company, Limited

Takashi Yasumura

Toshio Koishi

Chikashi Kawashima

Isao Tanaka

Akira Ishihara

Kazuhiko Yamamoto

Shuichi Inoue

Akira Kawada

Satoshi Nakahata

Kazumi Nejigaki

Yukitoshi Nishikawa

Takeshi Asanawa

The subject is the preparation of chlorotrifluoroethylene (CTFE) by a known reaction of 1,1,2-trichloro-1,2,2,-trifluoroethane (R-113) with zinc powder dispersed in an alcohol such as methanol, and the object of the invention is industrially easily and smoothly carrying out the reaction in a continuous manner. The disclosed process uses a plurality of stirred tank reactors, usually two or three reactors, which are connected to each other in a series arrangement by overflow pipes. A dispersion of zinc powder in an alcohol is continuously fed into the first reactor only so as to allow the dispersion to overflow into the next reactor and then into the remaining reactor(s) in turn, and R-113 is continuously fed into each reactor. CTFE is continuously discharged from each reactor, while zinc in the initially fed dispersion is gradually converted into zinc chloride. In the last reactor the conversion of zinc reaches 90% or above. Together with the remaining zinc powder the solution of zinc chloride in the alcohol is continuously discharged from the last reactor and can easily be recovered.

Continuous process for preparing chlorotrifluoroethylene

The invention relates to an optical fiber of the step-index type using quartz glass or an inorganic optical glass as the core material and a fluorine-containing resin as the cladding material. A copolymer of vinylidene fluoride with hexafluoroacetone, preferably at a molar ratio in the range from 96:4 to 88:12, is employed as the cladding material. Using such a copolymer, a highly transparent and very strong and tough cladding layer can easily be formed by a solution coating method.

Optical fiber having glass core and fluoro-copolymer cladding

The invention relates to an optical fiber of the step-index type in which the core material is poly(methyl methacrylate) or a copolymer of methyl methacrylate with another methacrylate or an acrylate. A copolymer of vinylidene fluoride with hexafluoroacetone is employed as the cladding material which makes good adhesion to the polymethacrylate core. When the amount of hexafluoroacetone is 4-20 mole %, the copolymer is low in crystallinity, high in transparency, appropriately low in refrax index and higher than 100.degree. C. in softening temperature, and can be extruded under the conditions suited to extrusion of poly(methyl methacrylate).

Optical fiber having polymethacrylate core and fluoro-copolymer cladding

A blend polymer composition, which is superior to polyvinylidene fluoride (PVDF) in impact resistance and retains favorable properties of PVDF, is obtained by blending 1-100 parts, and preferably 1-50 parts, by weight of a copolymer of vinylidene fluoride (VDF) and hexafluoroacetone (HFA) with 100 parts by weight of PVDF. Preferably the mole ratio of copolymerized VDF to HFA is from 96:4 to 50:50.

Polyvinylidene fluoride base blend polymer

Disclosed is a curable fluorine-containing copolymer, comprising 25-75 mol % of first repeating units which originate from chlorotrifluoroethylene, 10-70 mol % of second repeating units which originate from a vinyl or isopropenyl ester of fatty acid, such as vinyl acetate or isopropenyl acetate, 3-40 mol % of third repeating units which originate from a hydroxyl-containing allyl ether such as ethylene glycol monoallyl ether and 0-20 mol % of optional repeating units which originate from an optional monomer such as an acrylate. This copolymer possesses favorable properties characteristic of fluoro-resins, is soluble in organic liquids and is curable with a compound having a functional group that reacts with active hydrogen, such as a polyisocyanate. A coating liquid composition obtained by adding such a curing agent to a solution of the copolymer in an organic solvent is of wide use for painting and other coating purposes.

Curable fluorine-containing copolymer and coating liquid composition

A piezoelectric polymeric material in the form of sheet or film, which comprises polymers of vinylidene fluoride (VDF) as principle components. The piezoelectric material is essentially a mixture of 100 parts by weight of a VDF base resin, which may be either poly(VDF) or a copolymer, and 1-100 parts by weight of a copolymer of a fluoroelastomer and either VDF monomer or a monomer mixture containing a major amount of VDF monomer. A sheet or film having a high piezoelectric modulus is obtained by stretching a sheet or film of said mixture at an adequately elevated temperature and polarizing the sheet or film after or during the stretching thereby making the stretching sheet or film an electret.

Piezoelectric polymeric material

A fluorohydrocarbon resin that has elasticity and retains favorable properties of known fluorohydrocarbon polymers is obtained by graft copolymerization of a fluorine-containing elastomeric polymer with a fluorine-containing crystalline polymer. One of the elastomeric and crystalline polymers is prepared by copolymerizing at least one fluorine-containing monomer with at least one unsaturated monomer that has peroxy bond. When the elastomeric polymer is employed as the basic polymer and the crystalline polymer is polyvinylidene fluoride, the graft copolymerized fluorohydrocarbon resin is high in mutual solubility with polyvinylidene fluoride, so that the addition of this resin to polyvinylidene fluoride gives a resin composition which has elasticity and good low temperature characteristics.

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Fujimi, Japan

Takashi Yasumura