2 3 4
The examiner rejected the claims over the combination of Ardary, Lespade, Bendig and
Thompson.5
The invention relates to ceramic insulation. Applicants have claimed their invention using both
product (claims 20-21) and product-by-process (claims 22-32) format. No claims to a process per se
are before us. Claims 20, 22, 26 and 31, the independent claims, are reproduced below:
20. Ceramic insulation having a density between about 8-25 lb/ft a consistent3
microstructure, and improved strength, comprising a sol-gel binder fully gelled
through the entire thickness of the insulation and a ceramic component selected
from the group consisting of ceramic fibers, ceramic microparticles, and mixtures
thereof, the insulation optionally including a reacted metal forming refractory
ceramic bonds between ceramic components, the insulation being heat treated at
about 1000E F to have a tensile strength of at least about 0.244 MPa.
22. A ceramic insulation obtainable by:
(a) forming a slurry of ceramic fibers, ceramic microparticles, or mixtures
thereof, optionally, fugitive microparticles; and optionally, a metal;
(b) molding a slurry to form a soft felt mat of the ceramic components of the
slurry, the mat having a thickness;
(c) optionally, converting the metal to a binder to form bonds between the
ceramic components;
(d) impregnating the mat with a sol prior to drying the mat;
(e) gelling the sol to form a sol-gel binder which bonds between the ceramic
components so that the mat is dimensionally stabilized; and
(f) drying the mat to produce the ceramic insulation,
the insulation having a consistent micro structure, a tensile strength of at least about
0.244 MPa, uniform porosity, and a density of about 15 -22 lb/ft . 3
26. A ceramic insulation obtainable by:
(a) forming a slurry of ceramic components selected from the group consisting
of fibers, microparticles, and mixtures thereof:
(b) molding the slurry to form a wet mat;
(c) impregnating the wet mat with a sol;
2
Ardary et al., U.S. Patent 3,702,279 granted November 7, 1972.
3
Lespade et al., U.S. Patent 5,126,087 granted June 30, 1992.
4
Bendig, U.S. Patent 5,041,321 granted August 20, 1991.
5
Thompson, U.S. Patent 4,632,944 granted December 30, 1986.
2
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