Upgrading recycled polyvinyl butyral

Abstract

The invention is directed to a method for producing an upgraded polymer product from recycled polyvinyl butyral, to a polymer product obtainable by said method, to a construction material comprising such polymer product, and to a use of an extruder vacuum pump. The method of the invention comprises feeding a polymer feed stream to an extruder, wherein said polymer feed stream comprises a recycled polyvinyl butyral; melting said polymer feed stream in the extruder to produce polymer melt and passing said polymer melt through one or more degassing zones connected to a vacuum pump; measuring the melt flow index of the polymer product, wherein the vacuum pump is operated at a pressure that is controlled by the measured melt flow index of the polymer product.

Dependencies are inferred from the claim text.