摘要 |
The invention relates to mixtures of oligomeric phosphoric acid esters bearing hydroxyalkoxy groups, of the formula I <IMAGE> wherein q is an average chain length of 0.5 to 10, R1 is a hydroxyl-containing radical of the formula IIa, R2 is a radical of the formula III <IMAGE> R3 is a radical of the formula IIb, R4 = R1 or R3; R5, R6 and R7 are an H atom or an alkyl radical having 1 to 6 C atoms, m = 0 to 4 and n = 1 to 4. Additionally, the invention relates to a process for the preparation of the mixtures and their use as reactive flame retardants in polyurethane foams. |