摘要:
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
摘要:
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.
摘要:
A continuous process for the production of thermoplastically processable polyurethane elastomer is disclosed. The process comprise adding acid H compounds in an amount calculated to control and render constant the melt viscosity of the product. The inventive elastomer has constant melt flow behavior and high thermal stability.
摘要:
A mixture of hydroxy-terminated hydrocarbons useful as a mold release agent for polymers is disclosed. The polymers suitable in the present context are the ones prepared by polyaddition or polycondensation, in particular, thermoplastic polyurethane and polyurethane urea.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
This invention relates to thermoplastically processable, readily demouldable moulding compositions with low shrinkage and with a hardness of 65 to 85 Shore A, consisting of a mixture of A) a thermoplastic polyurethane of hardness 60 to 75 Shore A and B) a thermoplastic polyurethane of hardness 76 to 90 Shore A, which is produced continuously by a special multi-stage process.
摘要:
A process for producing a thermoplastic polyurethane film by means of sintering a particulate thermoplastic polyurethane in a heated mold, is described. The thermoplastic polyurethane has: (i) a melt index of 20 to 100, measured at 190° C. and under an applied force of 21.2 N; (ii) a relative solution viscosity of 1.15 to 1.45, the relative solution viscosity being determined by, measuring the viscosity (a) of a solution of 0.4 grams of the thermoplastic polyurethane in 99.7 grams N-methyl-2-pyrrolidone containing 0.1% dibutylamine at 25° C., measuring the viscosity (b) of N-methyl-2-pyrrolidone containing 0.1% dibutylamine at 25° C., and dividing viscosity (a) by viscosity (b); and (iii) a Shore hardness of 80 to 98.
摘要:
The invention relates to a process for continuously producing thermoplastically processable polyurethanes with improved softening behaviour in a sequence of static mixers.