摘要:
Polyisocyanates containing isocyanurate groups are prepared by a partial trimerization of (cyclo)aliphatic diisocyanates in the presence of at least one trimerization catalyst selected from the group consisting of tetraalkylammonium alkyl carbonates of the formula (I) ##STR1## (quaternary ammonioalkyl) carbonates having a betaine structure of the formula (II) ##STR2## and the preferred use of the polyisocyanates containing isocyanurate groups which are obtainable in this way is aspolyisocyanate component in polyurethane finishes.
摘要:
Stable (cyclo)aliphatic polyisocyanate compositions obtainable by phosgene-free methods, preferably by thermal cleavage of (cyclo)aliphatic polycarbamates, are stabilized with carbon dioxide, advantageously in an amount of up to 0.3% by weight.
摘要:
The invention relates to highly functionalized polyurethanes which are synthesized from molecules containing the functional groups A(B).sub.n, where A is an NCO group or a group reactive with an NCO group, B is an NCO group or a group reactive with an NCO group, A is reactive with B and n is a positive number and is at least equal to 2.
摘要:
A process for the preparation of polyisocyanates which contain one or more biuret groups, by reacting a) an aliphatic or cycloaliphatic isocyanate containing two or more isocyanate groups (isocyanate a) with b) a tertiary alcohol or a mixture of water and a tertiary alcohol (biuretizing agent b) at from 100 to 250° C., which comprises carrying out the reaction in the presence c) of a stabilizer (c) which constitutes a catalytic amount of urea, ammonia, biuret, a urea derivative of the formula I in which R1, R2, R3 and R4 are hydrogen, C1 to C10 alkyl or C5 to C10 aryl, or a carboxamide of the formula II in which R5 is C1 to C12 alkyl which is unsubstituted or in which 1, 2 or 3 hydrogen atoms are replaced by a radical
摘要:
Isocyanurate- and/or uretidone-containing polyisocyanates having a reduced color index and improved shelf life are prepared by conventional catalytic oligomerization of aliphatic and/or cycloaliphatic diisocyanates and treatment of the oligomerization products with peroxycarboxylic acids.
摘要:
In a process and an apparatus for preparing (cyclo)aliphatic polyisocyanates containing biuret groups from (cyclo)aliphatic diisocyanates and steam or a substance capable of splitting off water as reactants which are mixed with one another in a stirred reactor, the reactants are passes in countercurrent through a cascade-type stirred reactor comprising at least two stages. The dispersion of the gaseous reactant in the liquid reactant is reinforced by baffles installed in the stirred reactor. As baffles, use is made of discs provided with central openings and arranged at a distance from one another and/or strip baffles running in the longitudinal direction of the stirred reactor.
摘要:
The present invention relates to a process for the preparation of CFC-free, flexible polyurethane (molded) foams by reactingA) liquid polyisocyanate mixtures containing bonded urethane groups having a content of NCO groups of from 22 to 30% by weight which are themselves prepared by reacting a mixture of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates having a content of diphenylmethane diisocyanate isomers of from 55 to 99% by weight, based on the total weight, with at least one trifunctional polyoxypropylene-polyol having a hydroxyl number of from 20 to 60, withB) relatively high-molecular-weight polyhydroxyl compounds and, if desired,C) low-molecular-weight chain extenders and/or crosslinking agents,in the presence ofD) blowing agents,E) catalysts and, if desired,F) auxiliaries and/or additives,and to the polyisocyanate mixtures (A) modified by means of urethane groups which can be used according to the invention.
摘要:
The present invention relates to a process for preparing high-functionality polyetherols by reacting at least one trifunctional or higher-functionality alcohol and if appropriate further di- and/or monofunctional alcohols and/or modifying reagents, with the aid of acidic catalysts, where the trifunctional or higher-functionality alcohol is not glycerol. The present invention further relates to high-functionality polyetherols obtainable by such a process and to the use of these high-functionality polyetherols as adhesion promoters, thixotropic agents, rheology modifiers of polymers, phase transfer reagents, micro- or nanocontainers for biologically active compounds, for example for active medical ingredients, biocides, herbicides or fungicides, as pigment dispersants, an additive in printing inks or as structural units for preparing polyaddition or polycondensation polymers or for treatment of seed.
摘要:
Branched polyesters with sulfonate groups can be obtained by reacting components A, B, optionally C, and optionally D to yield branched polyesters, then reacting these branched polyesters with hydrogen sulfite. Component A is at least one α,β-olefinically unsaturated dicarboxylic acid, component B is at least one di- or higher-functional alcohol, optional component C is at least one di- or higher-functional carboxylic acid or hydroxycarboxylic acid without an α,β-olefinically unsaturated bond, and optional component D is at least one compound of formula CH3(—O—CH2—CH2)n—OH. In reacting the branched polyesters with hydrogen sulfite, a molar amount of hydrogen sulfite is at most 95 mol %, based on an amount of α,β-olefinically unsaturated dicarboxylic acid.
摘要:
The present invention relates to new high-functionality, highly branched or hyperbranched polylysines, to processes for preparing them, and to their use.