Highly microporous 2:1 layered silicate materials
AssigneeArmstrong World Industries, Inc.
InventorsWalter J. Bohrn, Kimberly S. Diffenbaugh, Shelly N. Garman, Jatin C. Khanpara
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Abstract
Lamellar-structured highly microporous silicate compositions are provided which can be used as insulative articles and insulation material. The silicate is in the form of lamellae selected from the group consisting of mica and vermiculite. The silicate lamellae form the microporous structure, by forming the pore walls with the lamellae. Processes are described which prepare these compositions by removing the water from flocculated or unflocculated aqueous dispersions of chemically delaminated silicates while the arrangement of the lamellae in the dispersion is largely preserved, resulting in the highly microporous lamellar structure.
Claims20
A process for the preparation of a porous lamellar structured 2:1 layered silicate material comprising flocculating an aqueous dispersion of chemically delaminated lamellae which are selected from the group consisting of mica and vermiculite, with a cationic flocculant which gives the lamellae interlayer cations and, with the lamellae, forms a floc which has an aqueous liquid medium, contacting the floc with a displacement solvent that has at least some miscibility with the aqueous liquid medium whereby the displacement solvent mixes with and extracts the aqueous liquid medium from the floc and drying the floc to leave the lamellae arranged in a lamellar structure, further providing that the lamellae do not collapse so that after the displacement solvent is removed in drying the lamellar structure is left with a pore volume greater than about 60%.
A process for the preparation of a porous lamellar-structured 2:1 layered silicate comprising lyophilizing a dispersion of chemically delaminated silicate lamellae, the said silicate lamellae being selected from the group consisting of mica and vermiculite lamella, further providing that the said dispersion has an aqueous liquid medium, whereby the aqueous liquid medium is removed leaving the silicate lamellae in a lamellar-structure having a pore volume greater than about 60%.
A microporous, 2:1 layered silicate composition comprising a porous, lamellar structure of chemically delaminated silicate lamellae in which the lamellae are selected from the group consisting of mica and vermiculite, wherein the lamellar structure has a single lamella which form walls of pores in the structure and wherein the lamellar structure has a pore volume greater than about 60%, with at least about 70% of that volume being in pores having a diameter less than about 100 microns, wherein further the chemically delaminated silicate lamellae were arranged in a liquid which was removed without causing a collapse of the lamellae to produce the lamellar structure.
Heat insulation comprising a porous, lamellar structure of chemically delaminated 2:1 layered silicate lamellae in which the lamellae are selected from the group consisting of mica and vermiculite, wherein the lamellar structure has single lamella which form walls of pores in the structure and where the lamellar structure has a pore volume greater than about 60% with at least about 10% of this pore volume in pores which, in at least one direction, have a diameter in the range of from about 0.05 to about 0.3 microns.
Dependencies are inferred from the claim text.