摘要:
Abstract of the Disclosure: Catalyst systems for the polymerization of C.sub.2 -C.sub.10 -alk-1-enes contain, as active components,a) a metallocene complex of the general formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum, X is halogen or C.sub.1 -C.sub.8 -alkyl, Y is carbon, phosphorus, sulfur, silicon or germanium, Z is C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.10 -cycloalkyl or C.sub.6 -C.sub.10 -aryl, R.sup.1 and R.sup.2 are identical or different and are each C.sub.1 -C.sub.4 -alkyl, R.sup.3 to R.sup.6 are identical or different and are each hydrogen or C.sub.1 -C.sub.8 -alkyl, or two adjacent radicals R.sup.3 and R.sup.4 and R.sup.5 and R.sup.6 in each case together form a hydrocarbon ring system of 4 to 15 carbon atoms and n is 0, 1 or 2, andb) an open-chain or cyclic alumoxane compound of the general formula II or III ##STR2## where R.sup.7 is C.sub.1 -C.sub.4 -alkyl and n is from 5 to 30. The novel catalyst systems are particularly suitable for the preparation of polyalk-1-enes having high molecular weights.
摘要:
Linear, thermoplastic, elastomneric copolymers of carbon monoxide and olefinically unsaturated compounds have an alternating sequence of repeating units and an average molecular weight Mw of the copolymers of from 80,000 to 1,200,000, binary, linear, alternating carbon monoxide/ethylene copolymers being excluded.
摘要:
Supertwist liquid crystal displays with outstanding properties are obtained when the nematic liquid crystal mixture contains at least one compound of the formula (I): ##STR1## where the variables are as defined in the disclosure.
摘要:
Benzene derivatives of the formula I ##STR1## in which n is 1 to 7, Q is --CO or --(CH.sub.2).sub.r -- where r is 1 to 5, s is 0, 1 or 2, t is 0 or 1, where s+t.gtoreq.1, X is F, Cl, --CF.sub.3, --CN, --OCF.sub.3 or --OCHF.sub.2, and Y, L and Z are each, independently of one another, H or F.
摘要:
Dienes of the formula I ##STR1## in which n is 0, 1, 2, 3, 4 or 5, r is 1, 2 or 3, s is 1 or 2, ##STR2## is trans-1,4-cyclohexylene or trans-1,3-dioxane-2,5-diyl, ##STR3## is trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, unfluorinated or mono- or polyfluorinated 1,4-phenylene, in which one or two CH groups may also be replaced by N, or the central part ##STR4## Z is a single bond, a bridging member selected from the group consisting of --CH.sub.2 CH.sub.2 --, --CH.dbd.CH--, --C.tbd.C--, --CO--O--, --CH.sub.2 O--, --OCH.sub.2 -- and --O--CO--, or any desired combination of two such bridging members, where two O atoms are not linked directly to one another, and R is --CN, --NCS, halogen or an alkyl, alkenyl, alkoxy or alkenyloxy group, in each case having up to 12 carbon atoms and in each case unsubstituted or monosubstituted or polysubstituted by fluorine and/or chlorine.
摘要:
The invention relates to a liquid-crystalline medium based on a mixture of polar compounds of positive dielectric anisotropy, characterized in that it contains one or more compounds of the general formula I ##STR1## in which X is fluorine, chlorine, CF.sub.3, OCF.sub.3 or OCHF.sub.2, one of the radicals 1.sup.1 and 1.sup.2 is fluorine, the other radical 1.sup.1 or 1.sup.2 is hydrogen and R is alkyl, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms.
摘要:
The invention relates to a matrix liquid crystal display containing integrated non-linear elements and a liquid crystal mixture which has a particularly high resistivity.
摘要:
The invention relates to a liquid-crystalline medium based on a mixture of polar compounds having positive dielectric anisotropy, characterized in that it contains one or more compounds of the general formula I ##STR1## in which r is o or 1, Q.sup.1 is --CH.sub.2 CH.sub.2 -- or a single bond, A is 1,4-phenylene or trans-1,4-cyclohexylene, L is H or F, R is alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl, in each case having up to 7 carbon atoms and X is F, CF.sub.3, or OCF.sub.2 H.
摘要:
The invention relates to a nematic liquid-crystal composition for active matrix displays with high voltage holding ratio and extremely good low temperature stability.
摘要:
The invention relates to 4,4'-disubstituted 2',3-difluorobiphenyls of the formula I ##STR1## in which n is 1 to 7, A is trans-1,4-cyclohexylene or 1,4-phenylene, r is 0 or 1, X is F, Cl, --CF.sub.3, --CHF.sub.2, --OCF.sub.3 or --OCHF.sub.2 and Z is H or F.