Intumescent flame retardants

Claim 1

A method for improving the color of a cured intumescent flame retardant composition comprising (A) the initial condensation of a polyol having from 5 to 15 carbon atoms per molecule and from 4 to 8 hydroxyl groups per molecule in an approximate amount ranging from 5 to 40 parts with a phosphorus oxide compound of the formula P 2 O 5 .xH 2 O wherein x is a number in the range of 0 to 3 in an approximate amount ranging from 10 to 75 parts, in the presence of 5 to 15 percent of an approximate amount ranging from 10 to 70 parts of a nitrogen compound selected from the group consisting of melamine, dicyandiamide, urea and dimethylurea, and a color improving amount of a color improving compound; (B) the addition to the mixture of step (A) of the balance of said nitrogen compound over a period of about 0.1-3 hours or more at a temperature of about 180°-300° C.; and (C) thereafter curing by heating the reaction mixture of step (B) to evolve gaseous products, said color improving compound being of the formula R--Y z having from 1 to 25 carbon atoms per molecule, wherein Y is selected from the group consisting of --OH, --COOH and --NR' 2 , z is a number having a value of 1, 2 and 3, R is an organic radical having a valence z selected from the group consisting of alkyl, cycloalkyl, alkoxy, aryl and combinations thereof, and R' is selected from the group consisting of --H and --R, wherein one of said R' groups can be joined with said R group to form a heterocyclic ring.

Claim 2

A method for improving the color of a cured intumescent flame retardant composition comprising (A) the initial condensation of a polyol having from 5 to 15 carbon atoms per molecule and from 4 to 8 hydroxyl groups per molecule in an approximate amount ranging from 5 to 40 parts with a phosphorus oxide compound of the formula P 2 O 5 .xH 2 O wherein x is a number in the range of 0 to 3 in an approximate amount ranging from 10 to 75 parts, in the presence of 5 to 15 percent of an approximate amount ranging from 10 to 70 parts of a nitrogen compound selected from the group consisting of melamine, dicyandiamide, urea and dimethylurea, and a color improving amount of a color improving compound; (B) the addition to the mixture of step (A) of the balance of said nitrogen compound over a period of about 0.1-3 hours or more at a temperature of about 180°-300° C.; and (C) thereafter curing by heating the reaction mixture of step (B) to evolve gaseous products, said color improving compound being of the formula R--Y z having from 1 to 25 carbon atoms per molecule, wherein Y is selected from the group consisting of --OH, --COOH and --NR' 2 , z is a number having a value of 1, 2 and 3, R is an organic radical having a valence z selected from the group consisting of alkyl, cycloalkyl, alkoxy, aryl and combinations thereof, and R' is selected from the group consisting of --H and --R, wherein one of said R' groups can be joined with said R group to form a heterocyclic ring.