Flame retarded high modulus polyurethane elastomers and method of making same
申请人:UNION CARBIDE CORPORATION
公开号:EP0197463A2
公开(公告)日:1986-10-15
A high modulus polyurethane elastomer having improved combustion resistance and satisfactory physical properties comprising the reaction product of a polyol or polymer polyol, a low molecular weight chain extender, a liquid organic polymeric isocyanate having an average functionality of at least about 2.4 and a defined concentration of flame retardant.
A mixture of brominated aromatic hydrocarbons is produced by a two-stage process involving reacting an aromatic hydrocarbon and bromine in a first stage to give a penta-bromo derivative, and then, in the presence of the first stage product, reacting a further quantity of aromatic hydrocarbon and bromine to give tri-bromo derivative or a mixture of di- and tri-bromo derivatives with the latter predominating.
The mixture may have 40-95 mole per cent of tri- or di- and tri-bromo derivatives, and 40-5 mole per cent of penta-bromo derivative with not more than 2 mole per cent of tetra-bromo derivatives.
The mixture is suitable as a well bore fluid, and can be varied in composition to give products with a range of specific gravities for that purpose. The substantial absence of tetra-bromo derivatives means that the products can be used without toxicological problems.