Abstract:
Proposed is a method for purifying a recycle stream (1) from a system for producing polyarylene ether sulfones by the polycondensation of aromatic bis-halogen compounds and aromatic bisphenols or salts thereof in the presence of at least one alkali metal- or ammonium carbonate or -hydrogen carbonate in an N-alkyl-2-pyrrolidone as a solvent, containing - 60 to 90% by weight water, - 10 to 40% by weight N-alkyl-2-pyrrolidone and, as a specification-detrimental impurity, up to 5000 ppm by weight of the alkyl succinimide corresponding to the N-alkyl-2-pyrrolidone and, in addition, up to 1000 ppm by weight additional high boilers relative to N-alkyl-2-pyrrolidone, in particular inorganic salts, each relative to the total weight of the recycle stream (1), the sum of the components being 100% by weight, to obtain a pure N-alkyl-2-pyrrolidone stream (2) that can be fed back into the system for producing polyarylene ether sulfones by purification by distillation which is characterized in that the purification by distillation is carried out in a dividing wall column (TK) that has a dividing wall (T) which is arranged in the longitudinal direction of the column and which divides the inner space of the dividing wall column (TK) into a supply region (A), a discharge region (B), an upper common column region (C) and a lower common column region (D), the recycle stream (1) being fed to the supply region (A) of said dividing wall column and divided in the dividing wall column (TK) into a bottom stream (7) containing N-methyl succinimide, a top stream (8) containing water and a pure NMP stream as a side stream (2) from the discharge region (B).
Abstract:
Methods are provided for preparing polymer mixtures having low residual monomer content. The methods comprise mixing the at least two polymers in a solvent to form a polymeric mixture, the polymeric mixture comprising at least one residual monomer; and adding an antisolvent to the polymeric mixture so as to separate the at least two polymers from the polymeric mixture, where the residual monomer is soluble in the antisolvent. In some embodiments, methods are provided for preparing at least two polymers having low residual monomer content, the methods comprise adding an antisolvent to a mixture of at least two polymers dissolved in a solvent so as to precipitate the at least two polymers from the solvent and anti-solvent. The methods provided avoid steps in dry blending of polymers and produces polymer blends that have low residual monomer content.
Abstract:
A package for microelectronic circuits includes a frame made of a high molecular weight plastic material, such as a liquid crystal polymer (LCP), attached to a flange, or leadframe. The plastic material is injection molded to the flange. Initial polymerization of the plastic material can occur in a liquid state and results in an intermediate material having an initial melting temperature. After the frame is injection molded, the frame is heated and undergoes further (secondary) polymerization, thereby lengthening polymer chains in the plastic material. These longer polymer chains have higher molecular weight, and the resulting final material has a higher melting temperature, than the intermediate material. The resulting ultra-high molecular weight polymer can withstand high temperatures, such as those encountered during soldering. Thus, after the further (secondary) polymerization, a die can be soldered to the flange, without damaging the plastic frame.
Abstract:
L'invention porte sur un procédé d'élimination d'ions métalliques dans une solution organique visqueuse,dont la viscosité à 20°C est comprise entre 1et 1000 cP. Ce procédé comprend les étapes consistant à disposer, dans une colonne, une résine échangeuse d'ions macroporeuse, ladite résine comprenant au moins une résine acide de typecarboxylique,à base d'un copolymère ayant des groupes actifs sous forme carboxylique (CO 2 H), puis à faire passer ladite solution organique visqueuse en continu sur ladite résine échangeuse d'ions.
Abstract:
The filter for gel shearing and particle filtration of molten polymer comprises a first layer of metal fibers of an average equivalent diameter between 8 and 65 μm. The cross-section of the metal fibers has two neighboring straight sides with an included angle of less than 90° and one or more irregularly shaped curved sides. The metal fibers have an average length of at least 6 mm. The metal fibers are bonded to each other by means of metal bonds; wherein the metal of the metal fibers of the first layer is the bonding agent forming the metal bonds. The filter comprises a second layer of metal fibers. The average equivalent diameter of the metal fibers of the second layer is smaller than the average equivalent diameter of the metal fibers of the first layer.
Abstract:
A polymer including a self-immolative polymer segment and a thermally-activated trigger moiety is described. The self-immolative polymer segment includes a head end, a tail end, and a plurality of repeating units. The trigger moiety includes a cycloaddition adduct that is covalently coupled to the head end of the self-immolative polymer segment. When the polymer is exposed to an activation temperature, the cycloaddition adduct undergoes retro-cycloaddition to release the self-immolative polymer segment. The self-immolative polymer segment then decomposes to sequentially release repeating units in a head-to-tail direction.
Abstract:
For laser sintering, a material includes at least one powder that has been treated by heat to modify at least one of: a melting temperature of the at least one powder; and a recrystallization temperature of the at least one powder and results in the narrowing of the melting curve of the treated material relative to the untreated material. The heating can include a series of heating steps. The treatment improves the efficacies of the SLS process and product quality.
Abstract:
Thermoplastic polyurethane (TPU) made using low free isocyanate monomer (LF) prepolymer, for example a prepolymer based on p-phenylene diisocyanate (PPDI) with low free isocyanate content, possess unique performance features including exceptional tear strength, low compression set, and an exceptional overall balance of physical properties including high temperature mechanical strength.
Abstract:
Vorgeschlagen wird ein Verfahren zur Aufreinigung eines Recycle-Stromes (1) aus einer Anlage zur Herstellung von Polyarylenethersulfonen durch Polykondensation von aromatischen Bishalogenverbindungen und aromatischen Bisphenolen oder deren Salzen in Gegenwart mindestens eines Alkalimetall- oder Ammoniumcarbonats oder -hydrogencarbonats in einem N-Alkyl-2-pyrrolidon als Lösungsmittel, enthaltend: - 60 bis 90 Gew. % Wasser, - 10 bis 40 Gew. % N-Alkyl-2-pyrrolidon und als spezifikationsschädliche. Verunreinigung bis zu 5000 Gew.-ppm des dem N-Alkyl-2-pyrrolidon entsprechenden Alkyl-succinimids und daneben bis zu 1000 Gew.-ppm weitere Schwersieder gegenüber N-Alkyl-2-pyrrolidon, insbesondere anorganische Salze, jeweils bezogen auf das Gesamtgewicht des Recycle-Stromes (1), wobei die Summe der Komponenten 100 Gew. % ergibt, unter Erhalt eines Rein-N-Alkyl-2-pyrrolidon-Stromes (2), der in die Anlage zur Herstellung von Polyarylenethersulfonen rückführbar ist, durch Reindestillation, das dadurch gekennzeichnet ist, dass die Reindestillation in einer Trennwandkolonne (TK) durchgeführt wird, mit einer Trennwand (T), die in Kolonnenlängsrichtung angeordnet ist und die den Innenraum der Trennwandkolonne (TK) in einen Zuführbereich (A), einen Entnahmebereich (B), einen oberen gemeinsamen Kolonnenbereich (C) sowie einen unteren gemeinsamen Kolonnenbereich (D) auftrennt, der der Recycle-Strom (1) im Zuführteil (A) derselben zugeführt wird und der in der Trennwandkolonne (TK) in einen Sumpfstrom (7) enthaltend N-Methylsuccinimid, einen Kopfstrom (8) enthaltend Wasser, sowie einen Rein-NMP-Strom als Seitenstrom (2) aus dem Entnahmeteil (B) aufgetrennt wird.