Abstract: Preparation of isobutene homopolymers or copolymers having a number average molecular weight of from 500 to 5 000 000 by polymerization of isobutene or an isobutene-comprising monomer mixture in the presence of a Lewis acid or a complex comprising a Lewis acid as polymerization catalyst, wherein the polymerization is carried out in the presence of at least one hemiacetal or full acetal which can be obtained by protic acid-catalyzed reaction of at least one C1-C12-hydrocarbyl alcohol with at least one aldehyde or ketone having from 1 to 12 carbon atoms.

Abstract: Preparation of isobutene homopolymers or copolymers having a number average molecular weight of from 500 to 5 000 000 by polymerization of isobutene or an isobutene-comprising monomer mixture in the presence of a Lewis acid or a complex comprising a Lewis acid as polymerization catalyst, wherein the polymerization is carried out in the presence of at least one hemiacetal or full acetal which can be obtained by protic acid-catalyzed reaction of at least one C1-C12-hydrocarbyl alcohol with at least one aldehyde or ketone having from 1 to 12 carbon atoms.

Abstract: The present invention relates to a process for preparing polyisobutene by polymerizing isobutene using an inert diluent and a halogen-containing Lewis acid as a catalyst, wherein the isobutene in the form of droplets is contacted with the Lewis acid in a polymerization apparatus.

Abstract: The present invention relates to a process for preparing polyisobutenes by polymerizing isobutene in the presence of a Lewis acid catalyst in liquid organic phase, terminating the reaction by admixing the organic phase with an aqueous terminator in a dynamic mixer which has a rotationally symmetric mixing chamber formed from one circumferential wall and two end walls, and a mixing rotor driven such that it rotates therein, the organic phase being introduced through a first inlet orifice provided in the circumferential wall and the aqueous terminator via a second inlet orifice provided in the circumferential wall, and removing a finely dispersed mixture of the organic phase and of the terminator through an outlet orifice provided in the circumferential wall and feeding it to a phase separation. The process serves to prepare high-reactivity polyisobutenes and/or polyisobutenes with narrow molecular weight distribution.

Abstract: The present invention relates to a process for preparing polyisobutene by polymerizing isobutene using an inert diluent and a halogen-containing Lewis acid as a catalyst, wherein the isobutene in the form of droplets is contacted with the Lewis acid in a polymerization apparatus.

Abstract: A process for producing continuous filament fibers from a hydroxy- or amino-alkyl-melamine modified melamine-formaldehyde condensation product comprises filtering the highly concentrated aqueous solution of the melamine-formaldehyde condensation product, forcing the filtrate through a spinneret, drying the extruded filaments in a drying shaft by means of hot air, and treating the dried filaments in a tempering oven at temperatures which rise gradually to a maximum temperature of from 160 to 250.degree. C. to cure the precondensate.