| abstract |
Cellulosic boards, such as hardboards, fiberboards and particle-boards, are flame retarded by incorporation of a synergistically acting alumina trihydrate-ulexite composition in the boards. The alumina trihydrate-ulexite flame-retarding agent provides a board of satisfactory strength properties with a flame spread at least equivalent to that of a commercial Class I-rated hardboard when the loading of the flame-retarding agent in the board is kept at 50% or below of the total weight of the flame-retarded board. |