Abstract: The present invention relates to a process for the preparation of low-density flexible polyurethane foams comprising reacting, in a closed mold, a mixture comprising polyisocyanates; compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from about 400 to about 10,000; water as blowing agent; optionally, compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight in the range from 32 to 399 as chain-extending and crosslinking agents; and optionally, one or more known auxiliaries and additives, wherein one or more of the reaction mixture components is heated before foaming to a temperature of at least 40.degree. C.

Abstract: This invention relates to liquid urethane-modified polyisocyanate compositions obtained by reaction of polyisocyanates or polyisocyanate mixtures of the diphenylmethane series containing from about 50 to about 100% by weight diisocyanatodiphenylmethane isomers with substoichiometric quantities of polyether polyol compositions having an average hydroxyl equivalent weight of about 500 to 3000 and an average hydroxyl functionality greater than about 4, optionally followed by mixing the initially formed reaction product with urethane-free polyisocyanates or polyisocyanate mixtures of the diphenylmethane series containing from about 40 to about 100% by weight diisocyanatodiphenylmethane isomers. This invention also relates to a process for the preparation of such polyisocyanate compositions. The invention further relates to the use of such compositions as the polyisocyanate component in the production of flexible polyurethane foams.

Abstract: Elastic molded articles having a closed surface layer are made from polyurea elastomers by the reaction injection molding technique. These polyurea elastomers are prepared from a polyisocyanate in which all of the isocyanate groups are aromatically bound, a polyether and a diamine. The polyether has at least two isocyanate-reactive groups and a molecular weight from 1800 to 12,000. At least 50% of the isocyanate-reactive groups in the polyether are pjrimary and/or secondary amino groups. The diamine has a molecular weight from 108 to 400 and primary and/or secondary aromatically bound amino groups. Known auxiliary agents and additives may also be employed.

Abstract: Elastic molded articles having a closed surface layer are made from polyurea elastomers by the reaction injection molding technique. These polyurea elastomers are prepared from a polyisocyanate in which all of the isocyanate groups are aromatically bound, a polyether and a diamine. The polyether has at least two isocyanate-reactive groups and a molecular weight from 1800 to 12,000. At least 50% of the isocyanate-reactive groups in the polyether are primary and/or secondary amino groups. The diamine has a molecular weight from 108 to 400 and primary and/or secondary aromatically bound amino groups. Known auxiliary agents and additives may also be employed.

Abstract: The present invention is directed to a process for the production of urea- and/or biuret-modified polyisocyanates by reacting organic polyisocyanates with a mixture of high molecular weight isocyanate-reactive compounds and low molecular weight isocyanate-reactive compounds, wherein at least 25% of the isocyanate-reactive groups are primary amino groups. The present invention is further directed to the products obtained by this process and their use for the production of polyisocyanate polyaddition products, especially for the preparation of molded articles by the RIM process.

Abstract: The present invention relates to a process for the production of polyurethane-urea or polyurea-based microcellular of foam moldings by reacting a polyisocyanate component containing aromatically bound isocyanate groups with an isocyanate-reactive component containing at least one compound which has at least three aliphatic ether groups and aliphatically bound isocyanate-reactive groups and wherein a portion of the aliphatically bound-reactive groups are amino groups which have been converted to ammonium carbamate, carbonate or bicarbonate groups.The present invention also relates to the compounds containing aliphatic ether groups and ammonium carbamate, carbonate or bicarbonate groups, optionally in admixture with compounds containing unmodified amino groups or other known isocyanate-reactive compounds.

Abstract: Urethane-modified polyisocyanates having an NCO-content of from 5 to 45 wt. % are made by reacting an organic polyisocyanate or mixture of polyisocyanates having an NCO-content of from 30 to 50 wt. % with an organic polyhydroxyl compound or mixtures of polyhydroxyl compounds. The organic polyhydroxyl compound must include at least 10 hydroxyl equivalent percent of an alkoxylation product of a bisphenol corresponding to a specified formula containing two alcoholic hydroxyl groups and having an OH number of from 112 to 389. The reactants are employed in quantities such that the NCO:OH equivalent ratio is from 2:1 to 50:1. The urethane-modified polyisocyanates of the present invention are particularly useful in the production of polyurethanes by the isocyanate polyaddition process.

Abstract: The present invention is directed to a process for the production of polyurea-based microcellular moldings comprising reacting(a) at least one diisocyanate or polyisocyanate containing only aromatically bound isocyanate groups,(b) at least one compound containing at least two isocyanate-reactive groups, and(c) optionally the auxiliaries and additives known in polyurethane chemistry, in closed molds, components (a)-(c) being processed as a one-shot system by reaction injection molding, characterized in that component (b) comprises at least one polyether compound (b1) optionally in admixture with other isocyanate-reactive compounds and containing at least 3 aliphatically bonded ether groups and n-aliphatically bonded isocyanate-reactive groups, n standing for an integer or, statistically a fraction of from 2-4(i) at least (100:n) % of the isocyanate-reactive groups present in component (b1) being aliphatically bonded primary and/or secondary amino groups,(ii) at least 10 equivalent % of said amino groups being