Abstract: The invention relates to a multi-step process for the production of melt-processable polyurethanes with improved processing characteristics, particularly improved homogeneity.

Abstract: The present invention provides a process for the preparation of at least one of a polyurethane prepolymer and a polyurethane-urea prepolymer involving mixing in a mixing nozzle at least one diisocyanate with at least one of a polyhydroxyl compound and a polyamino compound having a molecular weight of from about 400 to about 10,000, the mixing nozzle including a first inlet, an annular nozzle channel having a substantially constant diameter, a second inlet and connected through a channel to a dwell line, wherein the first inlet is in communication with the annular nozzle channel through one or more apertures therein, introducing the polyhydroxyl compound and/or polyamino compound into the annular nozzle channel via the second inlet, injecting the diisocyanate through the one or more apertures into the polyhydroxyl compound and/or polyamino compound in the annular nozzle channel and reacting the mixture of diisocyanate and polyhydroxyl compound and/or polyamino compound in the dwell line.

Abstract: The present invention relates to a multi-stage process for the continuous preparation of thermoplastically processable polyurethanes with improved processing properties based on various polyols.

Abstract: Process for the continuous preparation of thermoplastically processable polyurethane elastomers with improved softening properties is disclosed. The process is carried out in a tubular reactor at a ratio of the circumferential speed of the stirrer (in m/sec) in the tubular reactor and the throughput (in g/sec) of >0.03 m/g.

Abstract: The present invention relates to a multi-stage process for the continuous preparation of thermoplastically processable polyurethanes with improved processing properties based on various polyols

Abstract: The present invention relates to a multi-stage process for the continuous preparation of thermoplastically processable polyurethanes with improved processing properties based on various polyols

Abstract: The present invention relates to a process for the production of molding compositions, which can easily be released from the mold. These molding compositions comprise thermoplastic polyurethanes with a hardness of 45 to 65 Shore A, with good mechanical properties, with low shrinkage and good low temperature properties.

Abstract: The present invention relates to a process for the production of molding compositions, which can easily be released from the mold. These molding compositions comprise thermoplastic polyurethanes with a hardness of 45 to 65 Shore A, with good mechanical properties, with low shrinkage and good low temperature properties.

Abstract: A continuous process for the preparation of a thermoplastic polyurethane elastomer is disclosed. The process is carried out at 130 to 250° C. and comprises reacting at least one polyether diol with at least one organic diisocyanate and 1,4-di-(2,2′-hydroxyethyl)-hydroquinone, in the presence of tin dioctoate as a catalyst. The resulting thermoplastic polyurethane has a glass transition temperature (Tg) below 50° C. The inventive thermoplastic polyurethane is suitable for making injection molded or extruded articles.

Abstract: A thermoplastic composition comprising aliphatic polyurethane is disclosed. The composition is charactrized in having a post weathering yellow value lower than 20 and good hardness and softening temperature values both before and after weatering for 504 hours in accordance with ISO 4892.

Abstract: Polyurethane moulding compositions which can be melt processed in the form of sintering powders suitable for the preparation of grained sintered films and which are prepared exclusively from linear aliphatic components are described. The polyol component is composed of 30 to 80 parts by weight of an aliphatic polycarbonate diol with an average molecular weight {overscore (M)}n of 1000 to 2200 and 70 to 20 parts by weight of a polybutane diol adipate and/or a polycaprolactone diol with an average molecular weight {overscore (M)}n of 1000 to 2400. Moreover, the mixture contains 1,6-hexamethylene diisocyanate in an equivalence ratio of 2.3:1.0 to 6.2:1.0, based on the polyol mixture and butane-1,4-diol as chain extender, the equivalence ratio of the butane-1,4-diol based on the poly mixture being 1.3:1.0 to 5.2:1.0.

Abstract: Process for the continuous preparation of thermoplastically processable polyurethane elastomers with improved softening properties is disclosed. The process is carried out in a tubular reactor at a ratio of the circumferential speed of the stirrer (in m/sec) in the tubular reactor and the throughput (in g/sec) of >0.03 m/g.

Abstract: A process for the continuous preparation of melt processable polyurethane elastomers having improved softening behavior is disclosed. The process entails reacting a polyisocyanate, a polyol and a chain extender, which have a temperature of at least 170° C., in a static mixer, wherein the reaction mixture is prepared. The reaction mixture is then metered into an extruder into which optional auxiliaries and/or further components are fed.

Abstract: The invention relates to a process for the continuous preparation of melt-processable polyurethanes, wherein an isocyanate-terminated prepolymer is intensively mixed with chain extender at temperatures of <200° C., and the mixture obtained is converted to melt processable polyurethane in a twin screw extruder under quasi-adiabatic reaction conditions.

Abstract: A process for the continuous production of a thermoplastic molding composition containing a mixture of a TPU and a thermoplastic (co)polymer is disclosed.

Abstract: A process for the preparation of a polyurethane-urea elastomer having a mole ratio of NCO groups to all active hydrogen atoms in the range of 0.9 to 1.2 is disclosed. The process comprise reacting (A), (B) and (C.2) for form an NCO-containing prepolymer and then reacting said prepolymer with (C.1) and (D). Accordingly (A) is 5-isocyanato-1-(isocyanatomethyl)-1,1,3-trimethylcyclohexane or bis-(4-isocyanatocyclohexyl)-methane,(B) is polytetrahydrofuran or hexanediol polycarbonate and (C.2) is a chain extender. (C.1) is 5-amino-3-amino-methyl-1,3,3-trimethylcyclohexane or bis-(4-aminocyclohexyl)-methane and (D) is a molecular weight regulator. The elastomer thus produced is particularly suitable for the preparation of moldings, films, flexible tubing (for medical purposes) and catheters.

Abstract: A thermoplastic molding composition comprising a thermoplastic polyurethane and a wax mixture is disclosed. The polyurethane is a product of an organic diisocyanate, a linear, hydroxyl-terminated polyol and a diol or diamine chain extender. The wax mixture contains a first mixture of an ester of a C.sub.10-45 aliphatic carboxylic acid and a diol, and an alkali metal or alkaline earth metal salt of a C.sub.10-45 aliphatic carboxylic acids, and at least one member selected from the group consisting of fatty acid ester, fatty acid amide, fatty acid ester amide and polyethylene wax.

Abstract: The invention relates to the continuous production of polyurethane and polyurethane urea prepolymers by reaction of polyisocyanates with isocyanate-reactive compounds in a mixing nozzle.

Abstract: The present invention relates to a process for the continuous production of thermoplastically processable polyurethanes having improved processing behaviour, wherein in a multistep reactionA) one or more linear hydroxyl-terminated polyols a) having a molecular weight of from 500 to 5000 are mixed continuously with a proportion of an organic diisocyanate b) in an NCO:OH ratio of from 2.0:1 to 5.0:1, in a mixing unit at high shear energy,B) the mixture prepared in step A) is reacted continuously to form an isocyanate-terminated prepolymer in a reactor at temperatures of >120.degree. C., until a conversion of >90%, referred to component a), is achieved,C) the prepolymer prepared in step B) is mixed with the remainder of component b), an NCO:OH ratio of from 2.05:1 to 6:1 being established overall in steps A) to C) and an NCO:OH ratio of 0.9 to 1.1 being established when all the components of steps A) to F) are included,D) the mixture prepared in step C) is cooled to a temperature of <190.degree. C.

Abstract: Thermoplastically processable polyurethane elastomers are produced by a process ofA) mixing one or more substantially linear macrodiols with a diisocyanate,B) reacting the resultant mixture in a reactor at temperatures of >100.degree. C. to form a prepolymer,C) mixing the prepolymer with one or more low molecular weight chain extenders, andD) reacting the mixture prepared in stage C) to complete conversion in a high-shear, high-viscosity reactor.