Bayer Aktiengesellschaft

Georg Niederdellmann

Bernd Quiring

Wilhelm Goyert

Hans Wagner

Ernst Grigat

Alfred Eitel

Ernst Meisert

Wilhelm Thoma

Wolfgang Grimm

Norbert Roemer

Wolfgang Wenzel

Hartmut Hetzel

Henning Klussmann

Hans Hespe

Horst Conrad

Jochen Wulff

Jurgen Schenk

The present invention is directed to a process for the production of matte, non-blocking, thin-walled molded articles, films or tubes from polyurethane elastomers prepared from high molecular weight polyols which contain dispersed polyadducts based on polyisocyanate polyaddition products. The use of these high molecular weight polyols contained dispersed polyadducts allows for the preparation of thin-walled, molded articles which have reduced surface tackiness. The present invention is additionally directed to the molded articles produced by this process and to their use for forming polyurethane foam composites.

Process for the production of matte, non-blocking, thin-walled molded

A process for the continuous glycolytic cleavage of polyurethane plastics waste in multi-shaft screw machines by the addition of optionally preheated diols, at a degradation temperature of 250.degree. C., while maintaining a pressure at least such that the polyurethane-diol mixture is in the liquid phase, by the discharge of the glycolysate mixture after short residence times of from 2 to 30 minutes in the reaction screw, and by rapid cooling of the glycolysate mixture.

Process for the continuous high temperature glycolytic cleavage of

The present invention is directed to a process for separating polyurethane hydrolyzates, preferably polyurethane foam hydrolyzates, into substantially amine-free foamable polyethers and diamines, comprising (a) (i) briefly expanding a hot polyurethane hydrolyzate obtained in a continuous screw extruder to normal pressure or in vacuo and, without using readily volatile components (ii) spraying said hydrolyzate directly into a tubular coil evaporator which is heated to 180.degree.-300.degree. C. and at the end of which a pressure of from 0.1 to 20 mbar is applied and (iii) separating a hydrolyzate containing less than 1% by weight of NH.sub.2 in a following cyclone from most of the diamine evaporated and all the solvent used, the diamine being separated from the solvent used in a following distillation column, optionally without any further heat input; (b) precipitating any diamine still present quantitatively in the form of its hydrochloride by introducing excess hydrogen chloride into the hydrolyzate, optionally diluted with inert solvents; and (c) the regenerated polyether obtained after removal by filtration of the precipitated amine salt being freed under reduced pressure from inert solvent and excess hydrogen chloride.

Process for separating polyurethane hydrolyzates into polyether and

The invention is directed to a process extruding or melt roll calendering thermoplastic polyurethanes wherein the polyurethanes used are synthesized from p1 (a) one or more relatively high molecular weight substantially linear polyols having molecular weights in the range from 400 to 10,000

Thermoplastic polyurethanes for processing in extruders and/or on

The instant invention is directed to a continuous process for the production of thermoplastic materials, comprising:

Process for the production of thermoplastic synthetic materials

The present invention relates to a process for the preparation of polyurethane ureas from relatively high molecular weight polyols, diisocyanates, water as chain lengthening agent and optionally short chain glycols in a multishaft extruder equipped with kneading elements.

Extrusion process for the preparation of polyurethane ureas

The instant invention is directed to a process for the separation of polyurethane hydrolysates into polyamines and polyols which can be used again for the production of polyurethanes, comprising introducing gaseous hydrogen chloride into the hydrolysate mixture which has optionally been diluted with an inert solvent, and removing the precipitated amine salt by filtration, characterized in that

Process for the separation of polyurethane foam hydrolysates into polyol

The instant invention is directed to a process for the modification of a thermoplastic polymer comprising:

Process for the production of thermoplastic polymer by introducing

The present invention relates to an improved continuous process for the preparation of polyurethane elastomers which are distinguished from the products produced by known processes by increased elasticity, reduced shrinkage, higher rigidity (limit bending stress), improved cold notched bar impact resistance and good thermal stability.

Process for the preparation of polyurethane elastomers in which at least

The instant invention is directed to a continuous process for the production of thermoplastic polyurethanes by reacting

Process for the production of thermoplastic polyurethane elastomers

The present disclosure is concerned with an improved method of reverse coating textile sheets with storage stable polyurethane top and adhesive coats which are formulated to have improved resistance to deformation under heat and pressure. At least one of the coats is formulated from a diisocyanate, a high molecular weight dihydroxy compound and a mixture of at least one low molecular weight diol with a low molecular weight monoalkanolamine. The coatings are applied in the usual reverse coating manner, i.e. the top coat is applied to a release substrate from solution; dried; the adhesive coat is applied from solution onto the dried top coat; and the textile substrate is laminated to the adhesive coat.

Method of reverse coating textile sheets with polyurethene

This application relates to textile sheets which have been coated with polyurethanes and to a process for coating said textile sheets wherein a solution of polyurethane is applied as a top coat to a release substrate and then a bonding coat is applied before application of the textile material. The polyurethane which is used as a top coat is prepared by reacting a dihydroxyl compound with a molecular weight between about 600 and 4000 and a mixture of at least 2 diols with a molecular weight between 62 and 450 with at least one organic diisocyanate. The invention overcomes the difficulty of the top coat being lifted from the release substrate in numerous areas while other areas remain firmly attached giving the so-called 'hoar-frost' effect.

Textile coating with polyurethanes

This invention relates to an improved process for the production of high molecular weight polyurethanes which are free from isocyanate groups and are soluble in organic solvent in reduced reaction times. The reactants, polyol and isocyanate, for example, are mixed together with solvent and the temperature is permitted to rise under the effect of the heat of reaction. The reaction mixture is then cooled with solvent addition in such a way that the viscosity of the reaction mixture remains constant until the optimum temperature for the polyurethane formation reaction ('specific reaction temperature') is reached. The mixture is then gradually cooled until there is no residual isocyanate present and the polymer is recovered from the reaction mixture.

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Dormagen, Germany

Georg Niederdellmann