GB1014043A - Isocyanate compositions - Google Patents

Abstract

Isocyanates are stabilized by incorporating a mixture of a triaryl phosphite and a phenolic antioxidant. The triaryl phosphite is a compound of a formula (RO)3P, wherein R is an aryl radical which may be substituted in an aromatic nucleus. Examples specified are triphenyl phosphite, tricresyl phosphite, tris-(-p nonylphenyl)phosphite, tri - beta - naphthyl phosphite, tris - (p - chlorophenyl) - phosphite and tris - (p - nitrophenyl) phosphite. The phenolic antioxidant is a phenol having antioxidant properties and in particular an orthosubstituted phenol and phenols carrying substituents, especially alkyl and aralkoxy substituents, in each of the positions orthoto the phenolic hydroxyl group, and bis-phenols corresponding with the following formulae <FORM:1014043/C2/1> ; <FORM:1014043/C2/2> wherein A is an alkylene or alkylidene radical or a sulphur atom, R1 is an alkyl or an alkoxy group and R2, R3 and R4 are hydrogen atoms or alkyl groups and may be the same or different. Specified examples are 2-(a -methylcyclohexyl)-4 : 6 - dimethylphenol, 2 : 6 - di - t - butyl - 4 - methylphenol, bis - (2 - (a - methylcyclohexyl-5-methyl - 2 - hydroxyphenyl) - methane, bis-(3-t-butyl - 5 - methyl - 2 - hydroxyphenyl) - ethane, bis - (3 - t - butyl - 5 - methyl - 2 - hydroxyphenyl) sulphide and styrenated phenol. Also suitable are polyhydric phenols which may be substituted in the aromatic nucleus, such as propyl gallate, 4-t-butylcatechol and hydroquinone. Specification 866,396 is referred to.