INORGANIC FIBER BOARD WITH BINDER OF THERMOSETTING RESIN AND THERMOPLASTIC VINYLIC RESIN

An inorganic fiber board having improved high resistance to splitting the board parallel to the plane of the board and an apparent density of from about 0.3 g/cm3 to 1.0 g/cm3 is produced by mixing 100 weight parts of an inorganic material consisting of 40-98 weight parts rock wool or slag wool, 2-30 weight parts asbestos and 0-50 weight parts of an inorganic filler with a binder of an aqueous emulsion of 3-25 weight parts (based on 100 weight parts of inorganic materials) of a thermosetting resin and 0.3-10 weight parts of a thermoplastic vinyl resin to obtain a slurry; dewatering the slurry on the screen to obtain a wet laid mat; and then drying and curing the mat to convert the thermosetting resin to an insoluble and infusible state. A surface decorated board is obtained by mixing vermiculite particles in the inorganic material. Another embodiment of a surface decorated board having a fine uneven crepe like pattern is obtained by rubbing the surface of a wet laid mat and applying suction to the other side of the mat repeatedly.