초록 ▼

A fire door comprising a core and edge banding, the principal ingredients of the core being expanded perlite, gypsum and cement, and including, as minor ingredients, an organic binder, and having a density not greater than about 35 lbs./cu. ft. The banding comprises composite stiles and rails, each

A fire door comprising a core and edge banding, the principal ingredients of the core being expanded perlite, gypsum and cement, and including, as minor ingredients, an organic binder, and having a density not greater than about 35 lbs./cu. ft. The banding comprises composite stiles and rails, each formed of a strip of wood and a strip of a cast mixture of which the principal ingredient is gypsum and including a binder and preferably also including fibers, unexpanded vermiculite and clay.

대표청구항 ▼

A fire door comprising a core and edge banding, the core comprising a molded mixture formed from particulate materials including at least 50 weight percent of expanded perlite, at least 10 weight percent of calcined gypsum and an aqueous binder, the molded core having a density of not greater than a

A fire door comprising a core and edge banding, the core comprising a molded mixture formed from particulate materials including at least 50 weight percent of expanded perlite, at least 10 weight percent of calcined gypsum and an aqueous binder, the molded core having a density of not greater than about 35 lbs./cu. ft., and the banding comprising composite banding elements each formed of a strip of wood and a strip of a cast mixture formed from an aqueous slurry of particulate materials including at least 60 weight percent of calcined gypsum, fibers, an accelerator and an aqueous binder, the cast strip having a density of at least 50 lbs./cu. ft., the wood and cast strips of each element being adhesively bonded to each other, and the banding elements being positioned at edges of the core and being secured to the core with the cast gypsum strip of each element presented inwardly toward the edge of the core.