Phosphorus-containing spirobi(meta-dioxane) phenolic polymers

Flame-resistant resins are prepared by heating at 100 DEG -150 DEG C. a phenol, condensed phosphoric acids and a 3,9-dialkenylspirobi(metadioxane) having the general formula: wherein each R1 is a hydrogen atom, a chlorine atom or a methyl group and each R2 is a hydrogen atom or a methyl group. Condensed phosphoric acids are those represented by the formula: wherein x is greater than 1; pyrophosphoric acid is the simplest member of this class, but usually a mixture prepared by reacting orthophosphoric acid and phosphorus pentoxide is used. Specified phenols include phenol itself, chlorophenol, resorcinol, p-phenylphenol, phloroglucinol, hydroquinone, cresol, m-xylenol, b -naphthol, coal tar or coal hydrogenation fractions, bis-phenols and tri-nuclear phenols such as 1,1,3-tris(p-hydroxyphenyl)propane, 1,1,3-tris(hydroxytolyl)propane, 1,1,3-tris(hydroxyphenyl)-2-methylpropane. The resin-forming reaction mixture usually includes an acidic catalyst such as sulphuric acid, toluene sulphonic acid, benzene sulphonic acid, boron trifluoride, aluminium chloride, dialkyl sulphates, titanium tetrachloride, phenyl acid phosphate and octylphenyl acid phosphate. In a modification, the 3,9-dialkenylspirobi(metadioxane) and phenol are reacted in the presence of an acid catalyst to produce a liquid precondensate A-stage resin which is then reacted with condensed phosphoric acids also in the presence of an acid catalyst; a small quantity of the condensed phosphoric acids may be used as the acid catalyst in the first stage. Examples 5-11 illustrate the two embodiments of the invention. Specification 666,732 is referred to. Reference has been directed by the Comptroller to Specifications 865,195 and 865,196.