| abstract |
The invention relates to elimination of discoloration in polyurethanes, particularly thermoplastic polyurethanes, by the addition to the reaction mixture from 0.01 to 1 percent by weight, based on the isocyanate component, a stabilizer package characterized as BHT and a compound selected from tris(nonylphenyl) phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, 2,2'-oxamido-bis[ethyl-3(3,5-dit-butyl-4-hydroxyphenyl)]propionate, disteryl thiodipropionate, triisodecyl phosphite, trilauryl trithiophosphite, distearyl pentaerythritol, 2,2'-ethylene bis(4,6-di-tertiarylbutylphenol), octadecyl 3-(3',5'-di-t-butyl-4'-hydroxy phenyl) propionate, 4,4'-thio-bis(2-t-butyl-5-methylphenol), 4,4'-thio-bis(2-t-butyl-5-methylphenol), 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, phenothiazine, tris(2,4-di-t-butylphenyl) phosphite, 4,4'-methylene bis(2,6-di-t-butylphenol), 2,6-di-t-butyldimethyl-aminomethylphenol and blends thereof. |