Abstract: The invention relates to a process for the removal of deposits formed in a reaction apparatus by the precipitation of solids from a liquid reaction mixture, which process is characterized in that particles of a material that is inert under the reaction conditions are introduced into the reaction apparatus, which particles, by suitable mechanical circulation of the reaction mixture, are so moved through the reactor that, during the reaction, by striking the walls or other built-in elements, they abrasively remove precipitates adhered thereto.

Abstract: The invention relates to a process for the removal of deposits formed in a reaction apparatus by the precipitation of solids from a liquid reaction mixture, which process is characterized in that particles of a material that is inert under the reaction conditions are introduced into the reaction apparatus, which particles, by suitable mechanical circulation of the reaction mixture, are so moved through the reactor that, during the reaction, by striking the walls or other built-in elements, they abrasively remove precipitates adhered thereto.

Abstract: The present invention relates to a process for preparing polyamide 6 (PA 6) by hydrolytic polymerization of &egr;-caprolactam. In a first reaction step, a first intermediate mixture is formed by ring opening &egr;-caprolactam in the presence of water, under conditions of increased pressure and temperature. The first intermediate mixture is then dehydrated to form a dehydrated intermediate having a water content of less than 0.5 wt. %. The dehydrated intermediate is subsequently polymerized to. produce a polyamide 6 product having a low dimer content (e.g., of less than 0.3 wt. %). The invention also relates to an apparatus in which the process may be performed. The apparatus includes, in sequence, a pressure reactor (23) having heat exchange surfaces (36), a dehydration device (24) that is in fluid communication with the pressure reactor (23), and a main reactor (25) that is in fluid communication with the dehydration device (24).

Abstract: A process for using low-molecular weight compounds that are water-extracted from (co)polyamides in the production of polyamide is disclosed. The process entails reacting these compounds with 10 to 15 wt. % water for a period of 3.5 to 6 hours at a temperature of 220° C. to 270° C., and polymerizing the resulting product along with caprolactam.

Abstract: A process for producing a polyamide or copolyamide freed from volatile constituents by removing the volatile constituents, in particular the monomers and dimers, in at least two stages from the polymer melt by using an, in particular, gaseous entrainer is described. The invention also relates to polyamide compositions made of polyamide 6 or a copolyamide with a reduced volatile constituent content, as well as moulding compositions made of the above-mentioned polyamides, and moulded articles and fibers which are produced from these moulding compositions.

Abstract: A process for removing low molecular weight constituents from polyamide 6 or from copolyamides based on caprolactam (herein (co)polyamide) is disclosed. The process comprise subjecting the (co)polyamide to liquid-extraction at a temperature which is above the boiling point of the liquid at atmospheric pressure said liquid containing water in an amount of at least 80 percent relative to its weight.

Abstract: A process for producing a polyamide or copolyamide freed from volatile constituents by removing the volatile constituents, in particular the monomers and dimers, in at least two stages from the polymer melt by using an, in particular, gaseous entrainer is described. The invention also relates to polyamide compositions made of polyamide 6 or a copolyamide with a reduced volatile constituent content, as well as moulding compositions made of the above-mentioned polyamides, and moulded articles and fibres which are produced from these moulding compositions.

Abstract: A process for removing low molecular weight constituents from polyamide 6 or from copolyamides based on caprolactam (herein (co)polyamide) is disclosed. The process comprise subjecting the (co)polyamide to liquid-extraction at a temperature which is above the boiling point of the liquid at atmospheric pressure said liquid containing water in an amount of at least 80 percent relative to its weight .

Abstract: A process for using low-molecular weight compounds that are water-extracted from (co)polyamides in the production of polyamide is disclosed. The process entails reacting these compounds with 10 to 15 wt. % water for a period of 3.5 to 6 hours at a temperature of 220° C. to 270° C., and polymerizing the resulting product along with caprolactam.