摘要:
Conjugated diolefins, optionally in combination with other unsaturated compounds which may be copolymerized with the diolefins, are polymerized by performing the polymerization of the diolefins in the presence of catalysts based on monocyclopentadienyl compounds of vanadium and alumoxanes in the presence of aromatic vinyl compounds as the solvent at temperatures of −30 C. to +80 C. By means of the process according to the invention, it is possible to straightforwardly produce solutions of polydiolefins, such as polybutadiene, having 1,2 unit contents of 10 to 30% in aromatic vinyl compounds, which solutions may then, for example, be further processed to yield ABS or HIPS.
摘要:
Vulcanizable, mercaptan- and/or xanthogen-disulfide-regulated polychloroprene rubber are produced by emulsion polymerization of chloroprene and, based on polymerizable monomer used, 0 to 30 parts by weight ethylenically unsaturated, other monomers copolymerizable with chloroprene in an alkaline medium by a process in which(1) 0.1 to 10 parts by weight of a tricyclic diterpene carboxylic acid containing at least two conjugated C.dbd.C double bonds per molecule, based on the polymerizable monomer used, and optionally(2) 0.1 to 5 parts by weight, based on polymerizable monomer used, fatty acid estersare used for their production.The polychloroprene produced in accordance with the invention may be used for the production of vulcanized rubber articles. The polychloroprene rubbers produced by the process according to the invention have a minimal tendency to foul metal molds. The pollution of wastewaters by the process according to the invention is minimal. The well-known favorable properties of polychloroprene remain unaffected.
摘要:
The combination of unmodified resinic acids and direct peptization in the production of sulfur-modified polychloroprene leads to a favorable ratio of elasticity to viscosity.
摘要:
High molecular weight, gel-free ethylene/vinyl acetate copolymers may be prepared by the process of solution polymerization if a particular relationship of temperature/pressure is observed.
摘要:
A carrier element for an IC module for incorporation into data carriers, in which the IC module is connectd with contact surfaces by means of leads, and the contact surfaces are designed for direct contacting.In order to protect the Integrated Circuit against destruction due to static charges, measures are provided to dissipate outside the circuit any portions of charge that may occur. In one embodiment, all terminals of the circuit have a low resistance connection with each other. The connection is suspended during each operational phase and is then restored. In a further embodiment, the terminals are bridged by spark gaps. This protective step is advantageous in that it is not necessary to remove and then restore the bridging.
摘要:
Provided are new partially hydrogenated nitrile rubbers which are distinguished by a specific ratio of viscosity to molecular weight, and also vulcanizable mixtures and vulcanizates based on said rubbers, and also the associated preparation processes. The partially hydrogenated nitrile rubbers lead to compounded formulations having advantageous processing properties in conjunction with excellent vulcanizate properties.
摘要:
A process of degrading nitrile rubbers comprises subjecting them to a metathesis reaction in the presence of specific catalysts with increased activity.
摘要:
An improved polymerization and work-up process makes it possible to produce specific nitrile rubbers which have a particular ion index which is responsible for an excellent vulcanization rate and leads to vulcanizates having an advantageous property profile.
摘要:
A novel process for reducing the molecular weight of nitrile rubber in the presence of specific catalyst systems containing the metathesis catalyst and also a specific addition of fluorine-containing boron compounds is provided.
摘要:
The present invention relates to specific water and solvent-free nitrile rubbers having specific functional groups and/or end groups, a process for the production thereof and the use thereof. This process involves removing volatile compounds from a fluid (F) containing (1) at least one nitrile rubber and (2) at least one volatile compound, wherein the process comprises at least the steps of a.) treating the fluid (F) in at least one conversation unit, b.) retreating the concentrated fluid from step a.) in at least one retreating unit and c.) feeding the retreated concentrated fluid from step b.) into at least one retreating unit.