METHOD OF PREPARING FIRE-RETARDANT COMPOSITION Russian patent published in 2010 - IPC B27K3/52 C09K21/12 

FIELD: chemistry.

SUBSTANCE: invention relates to preparation of fire-retardant solutions for treating wood and wood-based materials. The method is realised through condensation of carbamide and aldehyde in the presence of an amine with subsequent addition of orthophosphoric acid. Condensation is carried out in two steps. At the fist step the amine used is monoethanol amine and an ammonium salt of nitrile trimethylene phosphonic acid and condensation is carried out by successively mixing carbamide, 37% aqueous solution of formaldehyde, monoethanol amine and ammonium salt of nitrile trimethylene phosphonic acid in molar ratio equal to 1.0:1.3-2.5:0.1-0.2:0.005-0.08 respectively. At the second step acid condensation is carried out by adding orthophosphoric acid based on molar ratio of initial carbamide to orthophosphoric acid equal to 1.0:0.45-1.5.

EFFECT: method stabilises the technological process, improves fire-retardant properties of the end product, preserves outer appearance of the treated surface and reduces consumption during coating.

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