Abstract: Hydroxycarboxylic acid derivatives of the formula ##STR1## are particularly suitable for use as color developers in recording materials.

Abstract: Improved microcapsules have a capsule wall which contains a polyurethane which can be obtained by reacting an isocyanate with a polyether polyol which contains amino groups.

Abstract: A first reaction mixture, prepared from (a) isocyanates with isocyanate contents of from 5 to 50% and (b) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component "a" to component "b" of 0.8:1 to 5:1, from 0.1 to 20% of a blowing agent and, optionally, other known additives, is introduced into the rigid cavity of a closed mold. After this mixture has become resistant to permeation, but is still compressible, a second reaction mixture, either the same or different from the first reaction mixture, prepared from (c) isocyanates having isocyanate contents of from 5 to 50% and (d) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component "c" to component "d" of from 0.

Abstract: A homogeneous, storage-stable, emulsifier-free polyol mixture having a high mixed OH-number and a high ethylene glycol content comprising 100 parts of a relatively high molecular weight polyalkylene oxide polyol having an OH-number of from 20 to 210, which contains at least 5%, and less than 80%, by weight, of terminal ethylene oxide blocks, from 0.1 to 30 parts of a low molecular weight diol mixture having an OH-- number of 1200 to 1650 in the form of a reaction product of 1 mole of ethylene glycol with 0.1 to 0.5 moles of propylene oxide, optionally, up to 5 parts of di- and/or tri-functional compounds containing reactive hydrogen atoms and having a molecular weight of from 32 to 399, and optionally, other auxiliaries and additives known in the production of polyurethanes. Also, polyurethanes produced using these polyol mixtures.

Abstract: A first reaction mixture, prepared from (a) aromatic isocyanates with isocyanate contents of from 5 to 50%, and (b) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component "a" to component "b" of 0.8:1 to 5:1, from 0.1 to 20% of a blowing agent and, optionally, other known additives, is introduced into a closed mold with a rigid cavity. After this mixture has become resistant to permeation, but is still compressible, a second reaction mixture, prepared from (c) aliphatic and/or cycloaliphatic polyisocyanates having isocyanate contents of from 5 to 50% and (d) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component "c" to component "d" of from 0.

Abstract: A homogeneous, storage-stable, emulsifier-free polyol mixture having a high mixed OH-number and a high ethylene glycol content comprising 100 parts of a relatively high molecular weight polyalkylene oxide polyol having an OH-number of from 20 to 210, which contains at least 5%, and less than 80%, by weight, of terminal ethylene oxide blocks, from 0.1 to 30 parts of a low molecular weight diol mixture having an OH-number of 1200 to 1650 in the form of a reaction product of 1 mole of ethylene glycol with 0.1 to 0.5 moles of propylene oxide, optionally, up to 5 parts of di- and/or tri-functional compounds containing reactive hydrogen atoms and having a molecular weight of from 32 to 399, and optionally, other auxiliaries and additives known in the production of polyurethanes. Also, polyurethanes produced using these polyol mixtures.

Abstract: A single-phase, storage-stable, emulsifier-free polyol mixture comprising 100 parts of a relatively high molecular weight polyoxyalkylene polyol of OH number from 20 to 120, which has at least 5% and less than 80% by weight, of terminal oxyethylene blocks; from 1 to 100 parts of a low molecular weight diol mixture which is a reaction product of ethylene glycol, butane diol-1,4, or a mixture of ethylene glycol and butane diol-1,4, with from 0.05 to 0.50 mols of alkyl oxiranes; from 0.1 to 5 parts of solubilizing additives comprising one or more salts, the cations of which are from Groups I, II and III of the Periodic Table, ammonium or mono- to tetra-alkyl ammonium ions, and the anions of which are produced by removing at least one proton from an acid having a K.sub.s value of at least 10.sup.-7 ; and, optionally, other compounds having isocyanate-reactive hydrogen atoms and other auxiliaries and additives for polyurethane production. Also polyurethanes produced using these polyol mixtures.