Abstract: Process for producing polyamide powders by precipitation The present invention relates to a process for producing polyamide powders and to the polyamide powders obtainable by this process. The present invention additionally relates to the use of the polyamide powder as sintering powder in selective laser sintering.

Abstract: The present invention relates to a process for preparing a polyaryl ether by reacting components (a1) and (a2) in the presence of a carbonate compound (C) to obtain a salt-containing polymer (SP) comprising the polyaryl ether and a salt (S). After the reaction, the salt (S) is extracted from the salt-containing polymer (SP) to obtain a desalinated polymer (DP) comprising the polyaryl ether.

Abstract: The present invention relates to a process for preparing a polyaryl ether by reacting components (a1) and (a2) in the presence of a carbonate compound (C) to obtain a salt-containing polymer (SP) comprising the polyaryl ether and a salt (S). After the reaction, the salt (S) is extracted from the salt-containing polymer (SP) to obtain a desalinated polymer (DP) comprising the polyaryl ether.

Abstract: A method for desalinating a salt-containing polymer (SP) comprising a polyaryl ether having a softening temperature TS and a salt (S), comprising the steps of a) providing the salt-containing polymer (SP) at a first temperature T1 above the softening temperature TS of the polyaryl ether, b) contacting the salt-containing polymer (SP) provided in step a) with an extractant (E) to obtain a desalinated polymer (DP) comprising the polyaryl ether, and a salt-containing extractant (SE) comprising the extractant (E) and the salt (S).

Abstract: The present invention relates to a process for drying particulate polymers, comprising the steps of: a) providing a particulate polymer comprising from 60 wt % to 90 wt % of at least one solvent based on the total weight of particulate polymer and solvent, b) mechanically predrying the particulate polymer to a content of the at least one solvent of from 20 wt % to 50 wt % based on the total weight of particulate polymer and solvent, wherein the mechanical predrying in step b) is carried out with a roller press, and c) end-drying the particulate polymer to a content of the at least one solvent of from 0 wt % to 15 wt % based on the total weight of particulate polymer and solvent, wherein the particulate polymer is a polymer comprising repeating units of formulae I, II and/or III The present invention further relates to a process for working up particulate polymers.

Abstract: The invention relates to a process for producing polyarylene ether beads from a polyarylene ether solution, comprising the steps of i) dividing the polyarylene ether solution in a division apparatus which is made to vibrate with a frequency of 10 to 1400 Hz to obtain droplets, ii) transferring the droplets into a precipitation bath to form polyarylene ether beads in the precipitation bath which (A) comprises at least one aprotic solvent (component (1)) and at least one protic solvent (component (2)), (B) has a temperature of 0° C. to Tc, where the critical temperature Tc in [° C.] can be determined by the numerical equation Tc=(77?c)/0.58 in which c is the concentration of component (1) in the precipitation bath in [% by weight] and (C) has component (1) in concentrations of 5% by weight to cc, where the critical concentration cc in [% by weight] can be determined by the numerical equation cc=77?0.58*T in which T is the temperature in the precipitation bath in [° C.

Abstract: The invention relates to a method for synthesizing a polyamide, in which method an aqueous solution is sprayed onto the polyamide before and/or during a solid-state post-condensation process. The aqueous solution comprises at least a first compound, selected from the group comprising phosphoric acid, fully neutralized salts of phosphoric acid, partially neutralized salts of phosphoric acid, and mixtures thereof, and a second compound, selected from the group comprising an acid, an anhydride, a lactone, ammonia, an amine, and mixtures thereof, with the stipulation that the second compound is not phosphoric acid and is not phosphoric acid anhydride. The spraying occurs at a temperature that lies below the boiling point of water. A polyamide that can be produced by means of the method according to the invention can be used in particular to produce films, monofilaments, fibers, threads, or textile sheet materials.

Abstract: The present invention relates to a process for drying particulate polymers, comprising the steps of: a) providing a particulate polymer comprising from 60 wt % to 90 wt % of at least one solvent based on the total weight of particulate polymer and solvent, b) mechanically predrying the particulate polymer to a content of the at least one solvent of from 20 wt % to 50 wt % based on the total weight of particulate polymer and solvent, wherein the mechanical predrying in step b) is carried out with a roller press, and c) end-drying the particulate polymer to a content of the at least one solvent of from 0 wt % to 15 wt % based on the total weight of particulate polymer and solvent, wherein the particulate polymer is a polymer comprising repeating units of formulae I, II and/or III The present invention further relates to a process for working up particulate polymers.

Abstract: In a process for producing polyamides by polycondensation of polycondensable polyamide-forming monomers and/or oligomers in reaction mixtures comprising same, which may be water-containing but are free from organic solvents, the polycondensation is effected in an agitated reactor under agitation in a first step in the liquid phase and after a phase change taking place during the process in the same reactor is effected in a subsequent second step in the solid state, wherein the temperature in the reactor is below the melting point of the polyamide in the second step at least.

Abstract: The invention relates to a process for producing polyarylene ether beads from a polyarylene ether solution, comprising the steps of i) dividing the polyarylene ether solution in a division apparatus which is made to vibrate with a frequency of 10 to 1400 Hz to obtain droplets, ii) transferring the droplets into a precipitation bath to form polyarylene ether beads in the precipitation bath which (A) comprises at least one aprotic solvent (component (1)) and at least one protic solvent (component (2)), (B) has a temperature of 0° C. to Tc, where the critical temperature Tc in [° C.] can be determined by the numerical equation Tc=(77?c)/0.58 in which c is the concentration of component (1) in the precipitation bath in [% by weight] and (C) has component (1) in concentrations of 5% by weight to cc, where the critical concentration cc in [% by weight] can be determined by the numerical equation cc=77?0.58*T in which T is the temperature in the precipitation bath in [° C.

Abstract: The invention relates to a method for synthesizing a polyamide, in which method an aqueous solution is sprayed onto the polyamide before and/or during a solid-state postcondensation process. The aqueous solution comprises at least a first compound, selected from the group comprising phosphoric acid, fully neutralized salts of phosphoric acid, partially neutralized salts of phosphoric acid, and mixtures thereof, and a second compound, selected from the group comprising an acid, an anhydride, a lactone, ammonia, an amine, and mixtures thereof, with the stipulation that the second compound is not phosphoric acid and is not phosphoric acid anhydride. The spraying occurs at a temperature that lies below the boiling point of water. A polyamide that can be produced by means of the method according to the invention can be used in particular to produce films, monofilaments, fibers, threads, or textile sheet materials.

Abstract: The process for producing aromatic polyether sulfones via reaction of a dichlorodiphenyl sulfone component with a bisphenol component as monomers in the presence of alkali metal carbonate in the melt in the absence of solvents and diluents comprises carrying out the reaction in a mixing kneader which is operated with a shear rate in the range from 5 to 500 s?1.

Abstract: The process for producing aromatic polyether sulfones via reaction of a dichlorodiphenyl sulfone component with a bisphenol component as monomers in the presence of alkali metal carbonate in the melt in the absence of solvents and diluents comprises carrying out the reaction in a mixing kneader which is operated with a shear rate in the range from 5 to 500 s?1.

Abstract: In a process for producing polyamides by polycondensation of polycondensable polyamide-forming monomers and/or oligomers in reaction mixtures comprising same, which may be water-containing but are free from organic solvents, the polycondensation is effected in an agitated reactor under agitation in a first step in the liquid phase and after a phase change taking place during the process in the same reactor is effected in a subsequent second step in the solid state, wherein the temperature in the reactor is below the melting point of the polyamide in the second step at least.

Abstract: A process for producing polyamides from the corresponding monomers and/or prepolymers comprises the steps of (a) reacting the monomers and/or prepolymers and optionally further components under polyamide-forming reaction conditions to form polyamide, (b) treating the polyamide obtained in step (a) in a kneader above the melting temperature of the polyamide, (c) further processing the polyamide from step (b) into pellet, film, fiber or moldings, preferably pelletizing the polyamide, (d) extracting some or all unconverted monomers and any product dimers and oligomers and also optionally further components from the polyamide and/or drying the polyamide.