Process for the preparation of addition products from 1 mol dimerized or low degree oligodimerized 4,4'-diisocyanatodiphenyl methane and 2 or 3 moles 4,4'-diisocyanatodiphenyl methane, addition products thereof and their use in the preparation of polyurethane

摘要

The invention relates to a process for the dimerization of 4,4'-diisocyanatodiphenylmethane from emulsified form in non-polar solvents with the formation of addition compounds, and to the molecular compounds obtainable for the first time by this process from 1 mol of low molecular weight 4,4'-diisocyanatodiphenylmethane-uretdione or its lower oligomers with the idealized formula (I) IMAGE n 0 to 0.5 and n = average degree of oligomerization of the dimer; “Degree of oligodimerization”, and 2 to 3 moles of 4,4'-diisocyanatodiphenylmethane (MDI) IMAGE In the process according to the invention, 4,4'-diisocyanatodiphenylmethane (II) is emulsified in molten form in non-polar solvents, and the dimerization starts in the presence of conventional Dimerization catalysts at temperatures above the melting point of MDI, preferably up to 60 ° C., then lower the temperature, optionally interrupt the dimerization after an NCO content of 22.4 to 26.9% has been reached, and operate at low temperatures. The addition compound thus obtained from dimeric 4,4'-diisocyanatodiphenylmethane (with possibly only small proportions of oligomeric uretdione diisocyanates (I), n = 0.5) and 2 to 3 mol of 4,4'-diisocyanatodiphenylmethane is claimed as a new substance . Furthermore, the use of the addition compound for the optionally gradual construction of polyurethanes is claimed.