PHT-4 Diol is a reactive flame retardant, flame retardant mainly used for hardness polyurethane foams, adhesives and coatings.   PHT-4 Diol is a reactive flame retardant, mainly for the hardness of the polyurethane foam flame retardant adhesives and coatings. This product has the characteristics of high temperature and precipitation, non- corrosive metal surface, does not interfere with the stability of the catalyst. Soluble in alcohol, toluene, acetone, insoluble in water.