Abstract: The invention concerns a process and device for producing high-viscosity or highly stabilized, reaction-stable polyamides, in particular polyamide 6, with reactive amino end groups of less than 50 &mgr;eq/g and for continuously demonomerizing polyamides. The object of the invention is to produce simply, reliably and economically a high-viscosity or highly stabilized reaction-stable polyamide, in particular polyamide 6, and if necessary to carry out continuous demonomerization. According to the invention, the molten polyamide is brought into intimate contact, or intimately mixed with preheated nitrogen in a reaction system in at least one stage and a specific dwell time is set for the melt in a liquid phase. During the production of polyamide 6, expelled lactam is processed and fed to a polymerization reactor.

Abstract: In a method for the depolymerization and reprocessing of material which consists of polyamide 6 waste and/or oligomer-containing polyamide 6 waste and/or oligomer-containing lactam residues and/or oligomer-containing lactam by hydrolysis in a pressure reactor with the addition of water, the material is melted and the melt is conducted continuously at predetermined temperature through the pressure reactor the inside pressure of which is controlled by the dosaged feeding of water or steam.

Abstract: In a method for the depolymerization and reprocessing of material which consists of polyamide 6 waste and/or oligomer-containing polyamide 6 waste and/or oligomer-containing lactam residues and/or oligomer-containing lactam by hydrolysis in a pressure reactor with the addition of water, the material is melted and the melt is conducted continuously at predetermined temperature through the pressure reactor the inside pressure of which is controlled by the dosaged feeding of water or steam.

Abstract: A method to work-up waste material of polyethylene terephthalate (PET) in solid form and having a high initial viscosity for multivalent reuse and to recondense it to a high viscosity. The method includes the chemical regeneration and conversion of the recyclate in a mixture with a primary component in continuous and batchwise systems to form a homogenous product. The material to be reprocessed is heated in a stream of gas, crystallized, and dried. The solid-phase condensation is concluded in a stream of gas at high temperature. A transformation process is carried out by mixing the recycling material after treatment with a second component containing hydroxyl end groups.