| 摘要 |
A continuous process for the production of flame-resistant foamed plastics material by condensation of aqueous aminoplast precondensates with diisocyanates or polyisocyanates, wherein, in a first mixing stage, the isocyanate is mixed with 4 to 14% by weight of catalyst, the catalyst being an organic amine and/or an organic metal compound, at temperatures of 40 DEG to 130 DEG C., with a residence time of 1 to 8 seconds, and directly thereafter, in a second mixing stage, the aminoplast precondensate and, simultaneously but separately from the aminoplast, an acid curing catalyst are introduced, after which the foamable mixture thereby produced is discharged continuously. The apparatus for performing this process comprises two mixing chambers connected in series, the first mixing chamber being coolable and the mixing chambers being connected via a nozzle, the ratio of the cross-section on the narrowest point of the nozzle to the sum of the cross-sections of the feed lines supplying the first mixing chamber being 0.3:1 to 0.9:1. |
