Abstract: To provide a novel crosslinking system of fluorine-containing elastomer giving a crosslinked product particularly having improved mechanical strength and compression set at high temperature. A fluorine-containing rubber composition comprising a fluorine-containing elastomer having carboxyl group and/or alkoxycarbonyl group at an end of a trunk chain and/or branched chain as a crosslinkable group.

Abstract: The invention intends to obtain a transparent yttrium oxide sintered body of which in-line transmittance in a visible wavelength region of 400 to 800 nm at a thickness of 1 mm is 60% or more, without using aluminum that readily segregates in grain boundaries of yttrium oxide, without using special raw materials in which a silicon content is particularly reduced and without finely pulverizing raw materials. A transparent yttrium oxide sintered body that contains, with yttrium oxide as a main component, at least either one of tantalum or niobium or both thereof and has the in-line transmittance of 60% or more at a thickness of 1 mm in a visible wavelength region in the range of 400 to 800 nm.

Abstract: The present invention provides a process for preparing a fluorine-containing elastomer in a high productivity comparable to that of non-iodine transfer polymerization process by carrying out an iodine transfer polymerization at high pressure. The present invention also provides a fluorine-containing elastomer prepared by this process, and fluorine-containing molded articles. The process is a batch copolymerization process conducted under conditions that the reduced temperature of the critical constant is at least 0.95 and the reduced pressure of the critical constant is at least 0.

Abstract: The present invention provides a process for preparing a fluorine-containing polymer having few branched chains and little weight change in high temperatures, which is a new process wherein composition distribution substantially does not occur. The fluorine-containing polymer is prepared by a batch copolymerization process conducted under conditions of reduced temperature of at least 0.95 and reduced pressure of at least 0.80 of the critical constant calculated from critical temperature, critical pressure and composition ratio of each monomer in the gaseous phase of the reaction vessel using the Peng-Robinson formula; wherein when the number of monomer components in the target polymer is represented as n (n is an integer of 2 or larger), the name of each monomer component is represented as A1, A2, . . . An, the weight percentage of each monomer component A1, A2, . . . An of the target polymer composition is represented as a1, a2, . . .

Abstract: To provide a solid fluoroelastomer having nitrile group at the, end which gives a crosslinked product being excellent in heat resistance, solvent resistance, chemical resistance, compression set and cleanliness, and an economical process for preparation thereof. The process for preparing a nitrile group-containing fluoroelastomer by converting amide group contained in a polymer molecular chain of a solid fluoroelastomer into nitrile group in the presence of a dehydrating agent.

Abstract: The present invention provides a process for selectively separating HF and like acids present along with water-unstable organic acid fluorides.

Abstract: To provide a novel crosslinking system of fluorine-containing elastomer giving a crosslinked product particularly having improved mechanical strength and compression set at high temperature. A fluorine-containing rubber composition comprising a fluorine-containing elastomer having carboxyl group and/or alkoxycarbonyl group at an end of a trunk chain and/or branched chain as a crosslinkable group.

Abstract: There is provided a method of end-chlorination of a fluorine-containing compound which can easily provide a fluorine-containing monomer having a functional group such as nitrile group at relatively low cost. The method of chlorinating an end of a fluorine-containing compound having iodine atom at an end thereof comprises reacting a fluorine-containing organic compound having iodine atom at a molecular end thereof and represented by the formula (I): RfCX2I  (I) wherein Rf is an organic residue having fluorine atom, X is hydrogen atom or chlorine atom, with a chlorine gas at a temperature of from 150° C. to 180° C. under irradiation with light to cleave the C—I bond and replace iodine atom with chlorine atom.

Abstract: To provide a solid fluoroelastomer having nitrile group at the end which gives a crosslinked product being excellent in heat resistance, solvent resistance, chemical resistance, compression set and cleanliness, and an economical process for preparation thereof. The process for preparing a nitrile group-containing fluoroelastomer by converting amide group contained in a polymer molecular chain of a solid fluoroelastomer into nitrile group in the presence of a dehydrating agent.

Abstract: To provide a solid fluoroelastomer having nitrile group at the end which gives a crosslinked product being excellent in heat resistance, solvent resistance, chemical resistance, compression set and cleanliness, and an economical process for preparation thereof. The process for preparing a nitrile group-containing fluoroelastomer by converting amide group contained in a polymer molecular chain of a solid fluoroelastomer into nitrile group in the presence of a dehydrating agent.

Abstract: A coke oven operation management system capable of accomplishing unified management of an operation from receiving of stock coal to production and shipment of coke through management and control processing using a computer. A head office and branch offices of a concern determine basic schedules for production and shipment of coke and receiving of stock coal based on sale and self-consumption depending on a user's demand for coke and incoming information on coal from a colliery for every month and notify a production adjustment and management section of a coke production factory of the basic schedules, request the section of shipment of coke based on the user's demand, and instruct the section to receive coal.