Abstract: A process for the continuous production of linear thermoplastic polyesters comprises the following steps:(a) passing a transesterification or esterification product of an aliphatic or aromatic dicarboxylic acid having a molecular weight of <300 or an ester-forming derivative thereof with an aliphatic or cycloaliphatic diol having a molecular weight of <250 which may additionally contain a poly(alkylene oxide) glycol having a molecular weight of 400 to 4000 at from 250.degree. to 360.degree. C. under a pressure of 0.5 to 20 mmHg downward in the course of a residence time of from 3 to 10 minutes through an essentially upright tubular precondensation zone equipped with internal fitments having a free surface area of from 0.3 to 1.5 m.sup.2 /l to form a precondensate and a vaporous diol having a molecular weight <250,(b) separating into a precondensate and vaporous diol and(c) further condensing the precondensate in the bottom phase at from 240.degree. to 290.degree. C. under a pressure of from 0.

Abstract: A storage-stable, moisture-cured, single-component polyurethane system comprising(a) a polyurethane prepolymer having an NCO content of from about 1 to 10 weight percent prepared by the reaction of higher molecular polyols and aromatic polyisocyanates,(b) at least one polyaldimine having the structural formula ##STR1## in which R is a multivalent linear or branched or cyclic hydrocarbon radical, which optionally is interrupted by alkylene-, sulfonyl-, thio- and/or oxy groups as bridge members, or is a multivalent polyoxyalkylene radical,(c) optionally an aromatic and/or aliphatic carboxylic acid or arylsulfonic acid, and(d) optionally auxiliaries and/or additives.The polyurethane systems are useful as sealing, casting, patching, cementing and coating compounds.

Abstract: This invention relates to moisture tempered, storage stable, single component polyurethane systems prepared from a polyurethane prepolymer derived from an aromatic polyisocyanate, and a polyaldimine, which are used for preparing polyurethane elastomers or polyurethane coatings having improved temperature resistance.

Abstract: Diphenylmethane diisocyanate-based liquid polyisocyanate mixtures containing urethane groups and having an isocyanate content of from 12 to 30 percent by weight are obtained by reaction of a polyoxypropylene polyoxyethylene polyol containing 5 to 30 percent by weight of oxyethylene with diphenylmethane diisocyanate-based isocyanates. These polyisocyanate mixtures are storage stable at low temperature and yield flexible polyurethane foams having improved mechanical properties.