Abstract: The invention relates to a method for continuously producing copolyamides with melting points greater than approximately 265° C. According to the invention, in a continuous process, partially aromatic and partially crystalline polyamides of the following chemical systems with defined molar percentages of the individual components are produced during the synthesis of polymers: 30 to 50 mol % of aromatic dicarboxylic acids, which are derived from terephthalic acid; 30 to 50 mol % of aliphatic diamines, which are derived from hexamethylenediamine or of cycloaliphatic diamines having at least 6 C atoms, and; 0.5-25 mol % of aromatic diamines or cyclic diamines with at least 6 C atoms. The sum of all polymer-forming components add up to a composition of 100 mol %, and a stoichiometric ratio between amines and carboxylic acids exists.

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: A process and device for the standardised continuous production of polyamide 6, polyamide 6.6 and/or copolyamides from e-caprolactam and/or adipic acidic hexamethylenediamine or adipic acid and hexamethylenediamine uses a combination of known specific processes to design a polymerisation reactor in which product with sufficiently high quality can be produced with the most efficient possible use of the energy applied and in such a way that the initial substances can be used alternately in the individual processing stages: pre-heating of the initial products using a common heat exchanger to 190-300.degree. C.; polymerisation of the initial products in a pressure stage with or without elimination of water and product recycling at 150-280.degree. C. and a pressure of <20 bar, dewatering of the polymer melt in a one to five turn coil under slow pressure reduction; and final condensation of the melt in at least one common vertical reactor at temperatures of between 210 and 285.degree. C.

Abstract: A process and a device for continuous production of polyamides from a monomer starting material consisting (up to 100%) of adipic acid hexamethylene diamine and water are described. The process is characterized by completing of the first step under pressure at temperatures between 180 and 280.degree. C. in a closed reactor, after which the polyamide is subjected to further steps at the start of each of which vaporized water is removed or driven out by an inert gas.

Abstract: The invention concerns a process for continuously preparing polyamide 6 with a low dimer content from .epsilon.-caprolactam (fresh lactam) and/or from recycled lactams from extraction and melt-demonomerizing stages. In a plurality of process stages the recycled lactam and/or fresh lactam is hydrolyzed under pressure in the fusible state with water contents of between 3 and 15% and temperatures ranging from 220.degree. C. to 280.degree. C. With a lower constant water content being set, the molten polyamide is then fed to the polymerization process in a further pressure stage incorporating a gas chamber.

Abstract: The invention concerns a method of continuously producing polyamide 6 using recycled lactam from extraction and melt-demonomerizing stages. According to the invention, the cyclic oligomers present in the recycled lactam owing to the addition of .epsilon.-caprolactam (fresh lactam) are dissolved in the lactam as a function of the concentration of the oligomers in the product in use, at a dissolution temperature of between 120.degree. C. and 180.degree. C. The solution is then passed to a treatment, the solution preferably being introduced into a closed system and hydrolyzed in the fusible phase under pressure, at water contents of between 3 and 15% and temperatures ranging from 220 to 280.degree. C. With a constant low water content being set, the melt is then fed to the polymerization process in a further pressure stage incorporating a gas chamber (polymerizator).

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.