METHOD FOR PREPARING MODIFIED CARBAMIDOFORMALDEHYDE RESIN Russian patent published in 2005 - IPC

FIELD: chemical industry and technology.

SUBSTANCE: invention relates to technology for preparing modified methanol-free carbamidoformaldehyde resins. Modified carbamidoformaldehyde resin is prepared by condensation of carbamidoformaldehyde concentrate consisting of the following components, wt.-%: carbamide, 20.5-25.0; formaldehyde, 54.5-60.0; methanol, 0.3, not above, and water, the balance. Concentrate is condensed with the first portion of carbamide in the presence of furyl alcohol as a modifying agent in the mole ratio formaldehyde : carbamide = 1.9-2.1 by heating in medium with variable acidity followed by additional condensation of resin with additional carbamide portion up to the mole ratio formaldehyde : carbamide = 1.65-1.95. Furyl alcohol is added by two portions: firstly with the first portion of carbamide and then in the process of additional condensation with the second portion of carbamide up to the final mass ratio carbamide : furyl alcohol = 0.50-0.90. Invention provides optimization of conditions in synthesis of modified carbamidoformaldehyde resins allowing exclusion of toxic supra-resin waters in simultaneous reducing content of methanol. Carbamidoformaldehyde resins are used as binding agent in casting manufacture as component of sandy-resinous mixtures for ingots made of cast iron, nonferrous alloys and steel, in manufacture of splint-slab plates, composition materials and plywood.

EFFECT: improved preparing method.

1 tbl, 2 ex