Method of producing a flat body from a reactive polymer with high thickness accuracy and consistency

Claim 1

A process for the production of a reactive sheet-like structure which is solid at room temperature and of highly uniform thickness, from a mixture of a thermoplastically processable polymer. a low-viscosity ethylenically unsaturated compound as the crosslinking promoter and a crosslinking assistant. with or withtout further solid and/or liquid additives, by homogeneously mixing the components forming the reactive sheet-like structure, extruding the mixture and shaping the sheet-like structure of the desired thickness by calendering, wherein first of all the thermoplastically processable polymer, with or without additional, in particular solid, constituents of the mixture, is fed into a first zone - viewed in the direction of product flow - of a self-cleaning multi-screw extruder at a temperature below the melting point of the thermoplastically processable polymer, and conveyed into a second zone in which the thermoplastically processable polymer is melted and into which all, or the greater part, of the liquid, low-viscosity constituents of the mixture, and any other constituents which may be used, are then fed. all constituents of the mixture being homogeneously mixed in said zone ; the homogeneous melt is freed from undesirable volatile constituents in a downstream devolatilizing zone, after which the devolatilized melt is discharged from the extruder through a slot die ; and then, in order to obtain the desired thickness, the extruded sheet-like structure is passed directly through the nip of a pair of rolls at a temperature at which the sheet-like structure is at least partially irreversibly deformable under the processing conditions ; and wherein the sheet-like structure extruded through the slot die is fed to the pair of rolls at such a speed that a bank of material forms in front of the nip.