Stable modified polymer polyol dispersions

A stable modified polymer polyol dispersion of polymeric particles in a liquid polyol mixture, the stable modified polymer polyol dispersion is obtainable by a process comprising the preparation of polymeric particles, in the presence of the liquid polyol mixture, by

• a. reacting in the liquid polyol mixture and under polymerisation conditions
• at least one compound bearing at least one basic-nitrogen atom a.1) characterized by the presence in the molecule of at least one hydrogen atom attached to a nitrogen atom;
• with
• a mixture of compounds bearing a phosphorus atom a.2) comprising [bis(hydroxymethyl)phosphanyl]methanol (THP), a tetrakis(hydroxymethyl) phosphonium salt (THPX), [bis(hydroxymethyl)phosphoryl]methanol (THPO), ({[bis(hydroxymethyl)phosphanyl]methoxy}methanol (mTHP), {bis[(hydroxymethoxy)methyl]phosphanyl}methanol (dTHP), ({bis[(hydroxymethoxy)methyl]phosphanyl}methoxy)methanol (tTHP)), bis(hydroxymethyl)phosphorylmethoxymethanol (mTHPO), {bis[(hydroxymethoxy)methyl]phosphoryl}methanol (dTHPO) and ({bis[(hydroxymethoxy)methyl]phosphoryl}methoxy)methanol (tTHPO);
• or
• the mixture of condensation products a.3) resulting from the reaction of the mixture of compounds bearing a phosphorus atom a.2) as described above and at least one compound bearing at least one basic nitrogen atom a.1);
• wherein the compound bearing at least one basic-nitrogen atom a.1) is selected from
• melamine, trimethylol melamine, a compound of formula (I), a compound of formula (II);
• and
• mixtures thereof;
• wherein the compound of formula (I) is as follows
• R1—NH2 (I)
• wherein R1 is selected from —H, —(C1-C3)Alkyl, (C1-C3)Alkyl-CO—, NH2—CO—, —(CH2)n—NH2, —CN, —NH2, —SO2NH2, cyclohexyl, phenyl, —SO2OH and —NHCONHNH2;
• wherein n is an integer selected from 1-18;
• and the compound of formula (II) is as follows:
• wherein R2 is selected from NH═C<, O═C<, and S═C<;
• and R3 is selected from H, —CN, —NH2, —CONH2, —CONHCONH2, and —CONHCONHCONH2;
• wherein the liquid polyol mixture comprises at least one base polyol and at least one monofunctional polyetheramine, the monofunctional polyetheramine having a propylene oxide content selected from 30-99 wt %.