Flame Retarded Polyurethane Foam

A formulation comprising

• at least one polyol,
• at least one blowing agent,
• at least one catalyst,
• at least one surfactant,
• at least one isocyanate-reactive sulfur-containing compound selected from disulfides and sulfur-containing aromatic diamines, and
• at least one isocyanate-reactive brominated flame retardant selected from a) a mixed ester of tetrabromophthalic anhydride with diethylene glycol and propylene glycol, b) tribromoneopentyl alcohol, c) dibromoneopentyl glycol, and d) tetrabromobenzenedimethanol,
• with the proviso that when the isocyanate-reactive sulfur-containing compound is a sulfur-containing aromatic diamine, the isocyanate-reactive brominated flame retardant is a mixed ester of tetrabromophthalic anhydride with diethylene glycol and propylene glycol and/or 2,3-dibromoallyl alcohol,
• with the further proviso that when the isocyanate-reactive sulfur-containing compound is a sulfur-containing aromatic diamine and the isocyanate-reactive brominated flame retardant is a mixed ester of tetrabromophthalic anhydride with diethylene glycol and propylene glycol, the formulation comprises tribromoneopentyl alcohol.

A process for forming a rigid polyurethane foam, which process comprises contacting

• A) a polyisocyanate, and
• B) a formulation formed from
• at least one polyol,
• at least one blowing agent,
• at least one catalyst,
• at least one surfactant,
• at least one isocyanate-reactive sulfur-containing compound selected from disulfides and sulfur-containing aromatic diamines, and
• at least one isocyanate-reactive brominated flame retardant selected from a) a mixed ester of tetrabromophthalic anhydride with diethylene glycol and propylene glycol, b) tribromoneopentyl alcohol, c) dibromoneopentyl glycol, and d) tetrabromobenzenedimethanol, to form a mixture,
• with the proviso that when the isocyanate-reactive sulfur-containing compound is a sulfur-containing aromatic diamine, the isocyanate-reactive brominated flame retardant is a mixed ester of tetrabromophthalic anhydride with diethylene glycol and propylene glycol,
• with the further proviso that when the isocyanate-reactive sulfur-containing compound is a sulfur-containing aromatic diamine and the isocyanate-reactive brominated flame retardant is a mixed ester of tetrabromophthalic anhydride with diethylene glycol and propylene glycol, the formulation comprises tribromoneopentyl alcohol;
• and
• allowing the mixture to cure to form a rigid polyurethane foam.