PURPOSE: To simply obtain the subject ceiling board free from the irregularity of a coated adhesive without deteriorating the nonflammability thereof by coating inorganic fibers with the adhesive in the preparation of the inorganic fibers, forming the coated fibers into a mat, opening the mat, again laminating the opened fibers into a mat, and forming the mat into a desired shape by thermal press forming.
CONSTITUTION: The melted slag of a raw material is centrifugal with a spinning machine 1 and the prepared short fibers 11a are sprayed with an adhesive (e.g. a phenolic resin) 13, followed by forming the layered mat of monofilament on a belt conveyor 2. The mat 3 is loosened and cut into short fibers having an average length of 0.5-5mm with an opening machine 4, and laminated to a belt conveyor 5 to form a mat 6. The mat 6 is pressed with a pre-press machine 7 into a prescribed thickness and a specific gravity, cut into a prescribed size and subsequently hot-pressed into a prescribed thickness with a press machine 9 to provide the objective ceiling board 10.