VERFAHREN ZUR HERSTELLUNG VON MIKROZELLULAREN FORMKOERPERN
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 g...
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Zusammenfassung: | 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 present in the form of ammonium carbamate groups having a functionality of two in the isocyanate addition reaction, of the type obtained by reacting aliphatically bonded, primary or secondary amino groups with carbon dioxide, (iii) the unmodified compounds containing at least 3 ether groups having a molecular weight of from 200 to 10,000 and (iv) at least 0,2 equivalent % of all isocyanate-reactive groups of the total component (b) being ammonium carbamate groups. The present invention also relates to said compounds (b) optionally in admixture with the auxiliaries and additives known in polyurethane chemistry. |
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