摘要:
A process for preparing a tetrafluoroethylene/fluoro(alkyl vinyl ether) copolymer comprising polymerizing tetrafluoroethylene and fluoro(alkyl vinyl ether) in an aqueous suspension system which comprises a mixed medium of water and a fluorohydrocarbon or a chlorofluorohydrocarbon in a volume ratio of from 1:1 to 10:1 at a temperature of from 0.degree. to 25.degree. C. in the presence of a polymerization initiator of the formula:[Cl(CF.sub.2).sub.n --COO].sub.2 (I)wherein n is an integer of 1 to 10, the copolymer obtained by the process having a small number of unstable terminal groups and excellent flex life.
摘要:
A fluorine-containing copolymer comprising monomeric units of(a) tetrafluoroethylene,(b) 8 to 15% by weight of hexafluoropropene on the basis of the weight of the copolymer, and(c) 0.2 to 2% by weight of a fluoroalkyl vinyl ether of the formula:CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --CF.sub.2 X (I)wherein X is hydrogen or fluorine, and n is an integer of 3 to 9 on the basis of the weight of the copolymer, which has improved stress crack resistance, and flex resistance as well as good moldability.
摘要:
A fluorine-containing copolymer comprising monomeric units of:(a) tetrafluoroethylene,(b) 8 to 15% by weight of hexafluoropropene on the basis of the weight of the copolymer, and(c) 0.2 to 2% by weight of a fluoroalkyl vinyl ether of the formula:CF.sub.2 .dbd.CF--O--(CF.sub.2).sub.n --CF.sub.2 X wherein X is hydrogen or fluorine, and n is an integer of 3 to 9, on the basis of the weight of the copolymer, which has good moldability and improved stress crack resistance and flex resistance when formed as an article such as a film.
摘要:
Mixture of tetrafluoroethylene/hexafluoropropylene (TFE/HFP) copolymers comprising 5 to 20% by weight of hexafluoropropylene, the specific melt viscosity at 380.degree. C. of which is from 1.times.10.sup.4 to 60.times.10.sup.4 poise,(a) the melt flow ratio being at least 3.5, and(b) the zero strength time (ZST, second) at 380.degree. C. satisfying the following equation:ZST.gtoreq.1/3x.sup.2 +17x+107wherein x is (specific melt viscosity).times.10.sup.-4 having an improved extrudability, particularly an improved extrusion speed. These mixtures of copolymers contain a high specific melt viscosity portion and a low specific melt viscosity portion.
摘要:
A copolymer comprising monomeric units derived from ethylene, tetrafluoroethylene or chlorotrifluoroethylene and a fluorovinyl compound of the formula:CH.sub.2 .dbd.CFRf (I)wherein Rf is a C.sub.2 -C.sub.10 fluoroalkyl group, a molar ratio of ethylene and tetrafluoroethylene or chlorotrifluoroethylene being from 40:60 to 60:40 and the content of the fluorovinyl compound being from 0.1% to 10% by mole having improved thermal resistance and high temperature mechanical properties such as crack resistance.
摘要:
A copolymer comprising monomeric units of tetrafluoroethylene, ethylene and at least one monomeric compound selected from the group consisting of 2-trifluoromethylpropylene and 2-methyl-1,1,3,3,3-pentafluoropropylene, which has a improved crack resistance at a high temperature.
摘要:
A fluoroelastomer composition comprising (a) a fluoroelastomer having stabilized end group derived from an isoparaffin selected from the group consisting of isobutane, isopentane and isohexane, (b) at least one member selected from the group consisting of bivalent metal oxides, bivalent metal hydroxides and mixtures of bivalent metal oxide or metal hydroxide with metal salt of weak acid, (c) an aromatic polyhydroxy compound and (d) a quaternary ammonium compound of 8-alkyl- (or 8-aralkyl-)1,8-diazabicyclo[5.4.0]-7-undecenium, provides a fluoro-rubber having low compression set and excellent elastic properties and has excellent processing and storage properties. The fluoroelastomer can be cured with appropriate induction time and fast cure rate by the use of a specific curing agent system mentioned above.
摘要:
A power supply apparatus is provided which includes: a first switch provided between an inductor and a terminal to which a reference voltage is applied; a second switch provided between the inductor and an output terminal; a first comparator circuit that compares an input voltage with a first comparison voltage; a signal generating circuit that outputs a frequency signal according to an output from the first comparator circuit; and a first control circuit that controls the first and second switches based on an output from the signal generating circuit to control an electrical current flowing into the inductor.
摘要:
On a surface of a Si substrate, a nonvolatile memory cell, an nMOS transistor, and a pMOS transistor are formed, and thereafter an interlayer insulation film covering the nonvolatile memory cell, the nMOS transistor, and the pMOS transistor is formed. Next, in the interlayer insulation film, there are formed plural contact plugs connected respectively to a control gate of the nonvolatile memory cell, a source or a drain of the nMOS transistor, and a source or a drain of the pMOS transistor. Thereafter, there is formed a single-layer wiring connecting the control gate to the sources or drains of the nMOS transistor and the pMOS transistor via the plural contact plugs.
摘要:
An object of the present invention is to realize almost the same transmission characteristic in all wavelengths at a transmission rate of 10 Gb/s or more. An optical transmitter 10 outputs WDM signal light multiplexed with signal light of a plurality of wavelengths toward an optical transmission line 12. The optical transmission line 12 comprises an optical transmission fiber 14, an optical repeating amplifier 16 and a dispersion compensating fiber 18. The gain characteristic of the optical repeating amplifier 16 is set so that the gain becomes the maximum at the effective zero dispersion wavelength of the optical transmission line 12 and that lowers inversely proportional to the distance from the effective zero dispersion wavelength. The whole optical transmission line 12 is set so that the peak power deviation between the effective zero dispersion wavelength &lgr;0 and the wavelength &lgr;1 or &lgr;n on both end becomes approximately 4 dB.