Abstract: Polyamides, e.g., polyhexamethylene adipamide, are continuously produced via the following stages: Stage 1: into and through a reactor, polycondensing a liquid stream which contain the polyamide monomer(s) at a pressure P1 greater than atmospheric pressure, the stream of material at the outlet of the reactor including a vapor phase which contains steam and a liquid phase which at least contains the product of polycondensation; Stage 2: feeding the outlet stream of material into a chamber, evacuating at least a portion of the vapor phase therefrom and recovering at least the liquid phase which at least contains the product of polycondensation, the pressure P2 in the chamber being regulated at a set value such that it is greater than atmospheric pressure and the residence time of said liquid phase in the chamber being less than 5 minutes; and Stage 3: pressure reducing at least the liquid phase which at least contains the stream of polycondensation product recovered during Stage 2.

Abstract: The present invention relates to a novel process for the manufacture of nonwoven surfaces. It relates more particularly to a process for the manufacture of nonwoven surfaces by the process of direct melt spinning of continuous filaments arranged in the form of a sheet. This process employs a composition based on a thermoplastic polymer exhibiting an electrical conductivity sufficient to prevent the formation of electrostatic charges or to allow their removal during the spinning process.

Abstract: Spherical polyamide particles having a mean particle size of less than 1 mm, notably less than 100 ?m, are produced by dispersing the polyamide monomers in an inert liquid and then polymerizing same.

Abstract: Polyamides, e.g., polyhexamethylene adipamide, are continuously produced via the following stages: Stage 1: into and through a reactor, polycondensing a liquid stream which contain the polyamide monomer(s) at a pressure P1 greater than atmospheric pressure, the stream of material at the outlet of the reactor including a vapor phase which contains steam and a liquid phase which at least contains the product of polycondensation; Stage 2: feeding the outlet stream of material into a chamber, evacuating at least a portion of the vapor phase therefrom and recovering at least the liquid phase which at least contains the product of polycondensation, the pressure P2 in the chamber being regulated at a set value such that it is greater than atmospheric pressure and the residence time of said liquid phase in the chamber being less than 5 minutes; and Stage 3: pressure reducing at least the liquid phase which at least contains the stream of polycondensation product recovered during Stage 2.

Abstract: The invention relates to a novel method for the production of non-woven surfaces, in particular, a method for the production of non-woven surfaces by the process of direct spinning of molten filaments arranged in the form of a mat. Said method makes use of a composition of thermoplastic polymers with an electrical conductivity sufficient to either avoid the build-up of electrostatic charges, or to permit the removal thereof during the spinning process.

Abstract: Spherical polyamide particles having a mean particle size of less than 1 mm, notably less than 100 ?m, are produced by dispersing the polyamide monomers in an inert liquid and then polymerizing same.

Abstract: The invention relates to a continuous process for manufacturing polyamides. The polyamides are of the type obtained from diacids and diamines. The process comprises an operation of continuous mixing of a compound which is rich in amine end groups and a compound which is rich in acid end groups and a polycondensation operation using the mixture. The invention relates to the starting phase of such a process, during which an aqueous solution comprising a mixture of monomers in substantially stoichiometric proportions is used.

Abstract: The invention concerns a method for making polyamide. More particularly, the invention concerns a method for making polyamides derived from the reaction between a diacid and a diamine. It concerns a method for making a polyamide derived from the reaction of at least a diacid with at least a polyamide comprising the following steps: preparing a first mixture of diacid and diamine with a diacid/diamine molar ratio ranging between 0.8 and 0.995, preferably ranging between 0.95 and 0.99 in a first reactor (5); preparing a second mixture of diacid and diamine with a diacid/diamine molar ratio ranging between 1.005 and 1.2, preferably between 1.01 and 1.05, in a second reactor (4); introducing in melted form a first flow of the first mixture and a second flow of the second mixture in a stirred polymer reactor (7); drawing, preferably, continuously, from said reactor a flow of polyamide prepolymer; feeding said polyamide flow into a finishing step to obtain the desired degree of polymerisation.

Abstract: The invention relates to a continuous process for manufacturing polyamides. The polyamides are of the type obtained from diacids and diamines. The process comprises an operation of continuous mixing of a compound which is rich in amine end groups and a compound which is rich in acid end groups and a polycondensation operation using the mixture. The invention relates to the starting phase of such a process, during which an aqueous solution comprising a mixture of monomers in substantially stoichiometric proportions is used.