Flame Retardant Phosphate Ester Derivatives of Ortho Novolaks

The following examples illustrate the process and products of the invention but are not intended to limit the scope thereof. In these examples temperatures are given in degrees centrigrade and parts by weight unless indicated otherwise.

312 parts of a novolak resin containing about 90% o,o'-linkage and having a molecular weight of 350 was heated to 130.degree.. 140 parts of P.sub.2 O.sub.5 was then added in small increments. As the viscosity of the reaction mixture increased, the temperature was raised so that the mixture remained fluid. The last portion of P.sub.2 O.sub.5 was added at a temperature of 220.degree.. The reaction mixture became so viscous that it was not practical to add additional P.sub.2 O.sub.5. The mixture was allowed to cool and the resulting product was a dark colored brittle resin. The product was essentially completely soluble in warm 10% NaOH indicating the absence of a high degree of crosslinking.

Ina similar manner 312 parts of a randomly linked novolak with a molecular weight of 500 was reacted with P.sub.2 O.sub.5. After 75 parts had been added, the mixture became so viscous that further addition was impossible. The product was not soluble in hot 10% NaOH nor in common organic solvents, indicating a crosslinked gel.

The free phenol content of the ortho novolak resin used in Example 1 was reduced to less than 0.5% by distilling phenol off under reduced pressure. 595 parts of the resulting novolak, which now had a molecular weight of 550, was heated to 180.degree. and P.sub.2 O.sub.5 slowly added. After the addition of 130 parts, the reaction mixture became too viscous to continue. This product dissolved in warm 10% NaOH. At the point where 110 parts of P.sub.2 O.sub.5 had been reacted, the reaction mixture was sufficiently fluid to be easily stirred and aptly suited for molding applications.

590 parts of dephenolated novolak used in Example 3 was dissolved in 830 parts of chlorobenzene. The mixture was heated to 90.degree. and 261 parts of P.sub.2 O.sub.5 were added over a 1 hour period. The reaction temperature was then increased to 132.degree. and held for an additional 6 hours. It was noted that a trace amount of sticky solid adhered to the walls of the reactor. The solution was decanted into 6000 parts of hexane. A light pink solid precipitated in the form of a fine powder.

400 parts of an ortho novolak resin having a molecular weight of approximately 380 with less than 1% free phenol was placed in a stirred reactor. The resin was heated to 170.degree. and 71 parts of P.sub.2 O.sub.5 were added in small increments over a 3 hour period. Heating in the range of 170.degree.-175.degree. was continued over a 10 hour period. The viscosity was still in an acceptable range. The resin was then poured into a pan and allowed to harden. The product was a redish brown resin.

Solutions of the product of Example 5 were prepared with the following compositions:

Separately, the solutions were then tested by applying the solution to one side of a heavy kraft paper with an add-on such that 18 to 30% total solids were added. After drying the sheets were cured at 180.degree. under pressure for 30 minutes. The sheet were then glued to one side of a 3/4" thick fir plywood panel. In a radiant panel test the samples rated noncombustible.

In the manner of Examnple 4, 100 parts of an ortho novolak resin having a molecular weight of 380 and having less than 1% free phenol was reacted with 35.5 parts of P.sub.2 O.sub.5 using 89 parts of chlorobenzene as solvent. Twenty parts of the product thus obtained was slowly added to a pressure reactor containing 37 parts of ethylene oxide. The mixture was allowed to react for 20 hours at 25.degree.. The reactor was then opened and the unreacted ethylene oxide allowed to distill off. The product was a light colored liquid and amounted to 34 parts.

A solution of 132 parts of the product of Example 7 in 35 parts of methylene chloride was prepared. One part of n-methylmorpholine and one part of X521 silicone, a product of Union Carbide was added to the solution. The resulting mixture was rapidly mixed with 53 parts of toluene diisocyanate. A rigid foam results. The foam was exposed to direct flame and found to be self-extinguishing when the flame was removed.

In a like manner P.sub.2 O.sub.5 and P.sub.2 O.sub.3 may be substituted for P.sub.2 O.sub.5 in the foregoing examples with similar result.

While the present invention has been described with reference to certain specific embodiments, it will be recognized by those skilled in the art that many variations are possible without departing from the spirit and scope of the invention.