Abstract:
The present invention relates to the use of polyolefin copolymers A) for reducing color changes during the heating of polymer compositions which contain at least one thermoplastic polyamide B).
Abstract:
The present invention relates to a process for preparing an aliphatic or semiaromatic polyamide oligomer, in which an aqueous composition of the monomers is subjected to an oligomerization at elevated temperature and elevated pressure and the oligomerization output is preferably subjected to an expansion.
Abstract:
The invention relates to a process for continuously preparing polyamide oligomers. This comprises continuous conveying of an aqueous solution of polyamide-forming monomers from a reservoir vessel into an oligomerization reactor, heating of the aqueous solution beyond a dissolution or storage temperature, the residence time of the monomer solution in the oligomerization reactor being limited and the pressure or the partial vapor pressure of the water being adjusted such that a conversion of monomers to polyamide oligomers does not exceed a maximum value and/or the polyamide oligomers formed do not phase-separate or spontaneously crystallize in solid form, and continuous discharge of the polyamide oligomers from the oligomerization reactor. A polyamide oligomer preparable by this process can be provided continuously in a mixture with water in a process for preparing a semicrystalline or amorphous, thermoplastically processible polyamide and then postcondensed to give a polyamide. This polyamide can be used for production of moldings by means of injection molding, multicomponent injection molding, injection molding/welding, extrusion, coextrusion, blow molding or thermoforming.
Abstract:
The present invention relates to a process for the preparation of an aliphatic or partially aromatic polyamide, in which an aqueous composition of the monomers is subjected to an oligomerization at elevated temperature and increased pressure, the reaction mixture is optionally subjected to a first decompression to reduce the water content, the (optionally decompressed) reaction mixture is heated within a short time to a temperature above the melting temperature of the polyamides and the heated reaction mixture is subjected to a (further) decompression to reduce the water content and to an after-polymerization.
Abstract:
The invention relates to a process for continuously preparing polyamide oligomers. This comprises continuous conveying of an aqueous solution of polyamide-forming monomers from a reservoir vessel into an oligomerization reactor, heating of the aqueous solution beyond a dissolution or storage temperature, the residence time of the monomer solution in the oligomerization reactor being limited and the pressure or the partial vapor pressure of the water being adjusted such that a conversion of monomers to polyamide oligomers does not exceed a maximum value and/or the polyamide oligomers formed do not phase-separate or spontaneously crystallize in solid form, and continuous discharge of the polyamide oligomers from the oligomerization reactor. A polyamide oligomer preparable by this process can be provided continuously in a mixture with water in a process for preparing a semicrystalline or amorphous, thermoplastically processible polyamide and then postcondensed to give a polyamide. This polyamide can be used for production of moldings by means of injection molding, multicomponent injection molding, injection molding/welding, extrusion, coextrusion, blow molding or thermoforming.
Abstract:
A polyarylene ether sulfone comprising endgroups of formula (I), a process for its manufacture, a molding composition comprising the polyarylene ether sulfone, use of the molding composition and fiber, film or shaped article produced using the molding composition.
Abstract:
The present invention relates to a process for the preparation of an aliphatic or partially aromatic polyamide, in which an aqueous composition of the monomers is subjected to an oligomerization at elevated temperature and increased pressure, the reaction mixture is optionally subjected to a first decompression to reduce the water content, the (optionally decompressed) reaction mixture is heated within a short time to a temperature above the melting temperature of the polyamides and the heated reaction mixture is subjected to a (further) decompression to reduce the water content and to an after-polymerization.
Abstract:
The present invention relates to a process for preparing an aliphatic or semiaromatic polyamide oligomer, in which an aqueous composition of the monomers is subjected to an oligomerization at elevated temperature and elevated pressure and the oligomerization output is preferably subjected to an expansion.
Abstract:
The present invention relates to semi-aromatic copolyamides having a high glass transition temperature and a high degree of crystallinity, to a polyamide molding compound containing said semi-aromatic copolyamide and to the use of the semi-aromatic copolyamides and of the polyamide molding compounds.