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.

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, in which a polyamide prepolymer is subjected to a solid state polymerization.

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, in which a polyamide prepolymer is subjected to a solid state 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.

Abstract: A process for producing porous structures from polyamide by dissolving the polyamide in an ionic liquid and precipitating or coagulating the dissolved polyamide by contacting the solution with a liquid precipitant medium. Fibers are produced from the dissolved polyamide in a wet-spinning process by precipitation in protic solvents, in particular water, a C1-4-alkanol or mixtures thereof, and subsequent freeze-drying. Foils, films or coatings are produced by blade coating the dissolved polyamide onto a substrate surface, optionally spraying with protic solvent, in particular water, a C1-4-alcohol or mixtures thereof, dipping into a precipitation or coagulation bath, freeze-drying of the resulting foil, of the film or of the coated substrate. Molded parts are prepared by extracting the dissolved polyamide with protic solvents, preferably water, a C1-4-alcohol or mixtures thereof, wherein the dissolved polymer is transformed to a solid or wax-like state by cooling and extracted after subsequent molding.

Abstract: A process for producing porous structures from polyamide by dissolving the polyamide in an ionic liquid and precipitating or coagulating the dissolved polyamide by contacting the solution with a liquid precipitant medium. Fibers are produced from the dissolved polyamide in a wet-spinning process by precipitation in protic solvents, in particular water, a C1-4-alkanol or mixtures thereof, and subsequent freeze-drying. Foils, films or coatings are produced by blade coating the dissolved polyamide onto a substrate surface, optionally spraying with protic solvent, in particular water, a C1-4-alcohol or mixtures thereof, dipping into a precipitation or coagulation bath, freeze-drying of the resulting foil, of the film or of the coated substrate. Molded parts are prepared by extracting the dissolved polyamide with protic solvents, preferably water, a C1-4-alcohol or mixtures thereof, wherein the dissolved polymer is transformed to a solid or wax-like state by cooling and extracted after subsequent moulding.

Abstract: The present invention relates to a semicrystalline propylene polymer composition prepared by polymerizing propylene, ethylene and/or C4-C18-1-alkenes, where at least 50 mol % of the monomer units present stem from the polymerization of propylene and at least 20% by weight of the propylene polymer composition is the result of a polymerization using metallocene catalysts, with a melting point TM of from 65 to 170° C., where the semicrystalline propylene polymer composition can be broken down into from 65 to 85% by weight of a principal component A, from 10 to 35% by weight of an ancillary component B and from 0 to 25% by weight of an ancillary component C.

Abstract: Novel supported, titanized chromium catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins, a process for preparing them and to their use for the polymerization of olefins.

Abstract: Novel supported, titanized chromium catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins, a process for preparing them and to their use for the polymerization of olefins.

Abstract: The present invention relates to a semicrystalline propylene polymer composition prepared by polymerizing propylene, ethylene and/or C4-C18-1-alkenes, where at least 50 mol % of the monomer units present stem from the polymerization of propylene and at least 20% by weight of the propylene polymer composition is the result of a polymerization using metallocene catalysts, with a melting point TM of from 65 to 170° C., where the semicrystalline propylene polymer composition can be broken down into from 65 to 85% by weight of a principal component A, from 10 to 35% by weight of an ancillary component B and from 0 to 25% by weight of an ancillary component C, and where the proportions of components A, B and C are determined by carrying out TREF (temperature rising elution fractionation) in which that fraction of the propylene polymer composition which is soluble in xylene at (TM/2)+7.5° C. is firstly dissolved and separated off and then, as the temperature rises, at all of the higher temperatures 70° C., 75° C.

Abstract: Novel supported, titanized chromium catalysts for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins, a process for preparing them and to their use for the polymerization of olefins.

Abstract: Random copolymers of propylene with other 1-alkenes having up to carbon atoms, whose content of comonomers is in the range from 0.7 to 1.4% by weight if the only comonomer present in the propylene copolymers is ethylene, or whose content of comonomers is in the range from 0.7 to 3.0% by weight if at least one C4–C10-1-alkene is present as comonomer, and whose cold-xylene-soluble fraction is from 1.0 to 2.5% by weight if ethylene is present as a comonomer in the propylene copolymers, or whose cold-xylene-soluble fraction is from 0.75 to 2.0% by weight if the only comonomers present are C4–C10-1-alkenes, and a process for preparing the random copolymers of propylene is described, as is their use for producing films, fibers or moldings, and also the films, fibers and moldings themselves and biaxially stretched films made from random propylene copolymers of this type and processes for their production.

Abstract: Novel supported, titanized chromium catalysts can be used for the homopolymerization of ethylene and the copolymerization of ethylene with ?-olefins.

Abstract: Random copolymers of propylene with other 1-alkenes having up to carbon atoms, whose content of comonomers is in the range from 0.7 to 1.4% by weight if the only comonomer present in the propylene copolymers is ethylene, or whose content of comonomers is in the range from 0.7 to 3.0% by weight if at least one C4–C10-1-alkene is present as comonomer, and whose cold-xylene-soluble fraction is from 1.0 to 2.5% by weight if ethylene is present as a comonomer in the propylene copolymers, or whose cold-xylene-soluble fraction is from 0.75 to 2.0% by weight if the only comonomers present are C4–C10-1-alkenes, and a process for preparing the random copolymers of propylene is described, as is their use for producing films, fibers or moldings, and also the films, fibers and moldings themselves and biaxially stretched films made from random propylene copolymers of this type and processes for their production.

Abstract: Random copolymers of propylene with other 1-alkenes having up to carbon atoms, whose content of comonomers is in the range from 0.7 to 1.4% by weight if the only comonomer present in the propylene copolymers is ethylene, or whose content of comonomers is in the range from 0.7 to 3.0% by weight if at least one C4-C10-1-alkene is present as comonomer, and whose cold-xylene-soluble fraction is from 1.0 to 2.5% by weight if ethylene is present as a comonomer in the propylene copolymers, or whose cold-xylene-soluble fraction is from 0.75 to 2.0% by weight if the only comonomers present are C4-C10-1-alkenes, and a process for preparing the random copolymers of propylene is described, as is their use for producing films, fibers or moldings, and also the films, fibers and moldings themselves and biaxially stretched films made from random propylene copolymers of this type and processes for their production.

Abstract: Random copolymers of propylene with other 1-alkenes having up to carbon atoms, whose content of comonomers is in the range from 0.7 to 1.4% by weight if the only comonomer present in the propylene copolymers is ethylene, or whose content of comonomers is in the range from 0.7 to 3.0% by weight if at least one C4-C10-1-alkene is present as comonomer, and whose cold-xylene-soluble fraction is from 1.0 to 2.5% by weight if ethylene is present as a comonomer in the propylene copolymers, or whose cold-xylene-soluble fraction is from 0.75 to 2.0% by weight if the only comonomers present are C4-C10-1-alkenes, and a process for preparing the random copolymers of propylene is described, as is their use for producing films, fibers or moldings, and also the films, fibers and moldings themselves and biaxially stretched films made from random propylene copolymers of this type and processes for their production.

Abstract: The invention relates to a thermoplastic polymer mixture containing m, m representing a natural number higher than 1, polymers Pn wherein n represents a natural number between 1 and m, and at least one recurring functional group contained in the Pn polymer chain, said group(s) having the structure —(R1)x—C(O)—(R2)y— wherein x and y independently represent 0 or 1, and x+y=1, and R1, R2 independently represent oxygen or nitrogen linked into the main polymer chain. The polymers Pn differ in terms of at least one characteristic related to molecular weight. The polymer mixture has a number average molecular weight Mn(P)1, a weight average molecular weight Mw(P)1, a Z average molecular weight Mz(P)1, a heterogeneity index Mw(P)1/Mn(P)1, and a molecular weight Mp(P)1 defined according to DIN 55672-2 in hexafluoroisopropanol as an elution agent.

Abstract: A thermoplastic polymer mixture comprising m polymers Pn, where m is a natural number greater than 1 and n is a natural number from 1 to m, where n is a natural number from 1 to m, where each of the polymers has one or more functional groups of the structure