Fire door core
View Patent ↗The present invention describes an improved building material composition, useful for example as a fire door core and to improved methods of making this composition. The building material of the present invention is prepared from an aqueous mixture of expanded perlite and a fast setting, cementitious composition consisting essentially of a hydraulic cement having (1) a Portland cement and (2) a calcium aluminate cement, which composition can be molded and shaped into a fire door core.
1. A moldable composition useful for producing a fire door core comprising an aqueous mixture of expanded perlite and a fast setting, cementitious composition consisting essentially of a hydraulic cement having (1) a Portland cement and (2) a calcium aluminate cement, wherein the Portland cement (PC) and the calcium aluminate cement (CAC) are present in the fast setting cementitious composition in a weight ratio (PC:CAC) within the range of 4:1 to 8:1.
2. The composition of claim 1 containing an organic binder.
3. The composition of claim 2 wherein the Portland cement and the calcium aluminate cement are present in the fast setting cementitious composition in a weight ratio (PC:CAC) within the range of 5:1 to 7:1.
4. A building material composition useful as a fire door core, comprising a cured aqueous moldable mixture of expanded perlite, a fast setting, cementitious composition consisting essentially of a hydraulic cement having (1) a Portland cement and (2) a calcium aluminate cement, and an organic binder, wherein, the expanded perlite comprises about 50 to about 75 weight percent of the building material composition, the cementitious composition comprises about 20 to about 50 weight percent of the building material composition, the organic binder comprises about 1 to about 5 weight percent of the building material composition, and the Portland cement (PC) and the calcium aluminate cement (CAC) are present in the fast setting cementitious composition in a weight ratio (PC:CAC) within the range of 4:1 to 8:1.
5. The building material composition of claim 4 wherein the Portland cement and the calcium aluminate cement are present in the fast setting cementitious composition in a weight ratio (PC:CAC) within the range of 5:1 to 7:1.
6. The building material composition of claim 5 containing a fibrous reinforcement.
7. A building material composition prepared by drying an aqueous mixture of expanded perlite, a fast setting, cementitious composition consisting essentially of a hydraulic cement having (1) a Portland cement and (2) a calcium aluminate cement, and an organic binder, wherein, on a water-free basis, the expanded perlite comprises about 50 to about 75 weight percent of the aqueous mixture, the cementitious composition comprises about 20 to about 50 weight percent of the aqueous mixture, the organic binder comprises about 1 to about 5 weight percent of the aqueous mixture, and the Portland cement (PC) and the calcium aluminate cement (CAC) are present in the fast setting cementitious composition in a weight ratio (PC:CAC) within the range of 4:1 to 8:1.
8. A method for making a slab of building material suitable for making a fire door core from an aqueous mixture of materials, which method comprises mixing water, and as intermixed ingredients expanded perlite, a fast setting cementitious composition consisting essentially of a hydraulic cement having (1) a Portland cement and (2) a calcium aluminate cement, and an organic binder, wherein, on a water-free basis, the expanded perlite comprises about 50 to about 75 weight percent of the aqueous mixture, the cementitious composition comprises about 20 to about 50 weight percent of the aqueous mixture, the organic binder comprises about 1 to about 5 weight percent of the aqueous mixture, and the Portland cement (PC) and the calcium aluminate cement (CAC) are present in the fast setting cementitious composition in a weight ratio (PC:CAC) within the range of 4:1 to 8:1, the expanded perlite having a density less than about 6.5 lb./cu. ft., the water being present in an amount excess of the stoichiometric amount needed to hydrate the fast setting cementitious composition and sufficient to provide a damp mixture but less than an amount which would produce an aqueous slurry of the intermixed ingredients, placing a charge of the damp mixture having an original volume in a pressure mold of slab form, applying sufficient pressure to the charge in the mold to compress the charge into a compressed charge having about 25% to 33% of the original volume and maintaining the pressure until the compression strength of the compressed charge is at least about 50 psi to form a molded slab, removing the molded slab from the mold and thereafter drying the slab by heating it sufficiently to remove excess water.
9. The method as defined in claim 8 in which the organic binder is polyvinyl alcohol.
10. The method as defined in claim 9 in which the intermixed ingredients further include unexpanded vermiculite in an amount not greater than about 4 wt. % of the intermixed ingredients.
11. The method as defined in claim 8 in which the intermixed ingredients further include clay in an amount not greater than about 4 wt. % of the intermixed ingredients.
12. The method as defined in claim 8 which the intermixed ingredients further include fibrous reinforcements in an amount not greater than about 1 wt. % of the intermixed ingredients.