Abstract: A fire resistant fibrous composite article includes fibers bound together into a consolidated fibrous article such as a fiberboard. A first fire retardant composition including a hydrated mineral is in the interior of the article. A second fire retardant composition including a boron-containing compound is in the surface of the article. In another embodiment, a fire resistant fibrous composite article includes fibers, a fire retardant hydrated mineral and a zeolite bound together into a consolidated fibrous article which is resistant to water absorption. Another embodiment provides a lignocellulosic fibrous composite board for use in a roof system in which the board is exposed to bonding energy when it is bonded to another roof system component during construction of the roof. Another embodiment relates to a roof system of which a lignocellulosic fibrous composite board is part. The board or the roof system is in compliance with one or more fire resistance or flame and smoke standards.

Abstract: Wood pulp is bleached using hydrogen peroxide as the oxidative bleaching agent in the presence of magnesium hydroxide or magnesium oxide. The bleaching process is carried out in the presence of magnesium hydroxide as the predominant, and preferably essential, source of alkali. The process optionally includes transition metal chelants, such as DTPA or EDTA in the bleaching slurry. The process eliminates the need for added caustic and silicate in such systems and can be carried out at or near neutral pH of 5.0 to 8.5.