In re MacArthur

RICH, Judge.

This appeal is from the decision of the Patent Office Board of Appeals affirming the rejection of all 11 claims in appellants’ application, serial No. 657,917,1 filed August 2, 1967, for “Method for the Preparation of Compos*492ite Panels of Interfused Expanded Per-lite.” We affirm.

The Invention

Appellants’ invention is a method of making insulating structural panels of expanded perlite. Perlite is volcanic glass which contains silica, alumina, alkali metal oxides as well as small amounts of oxides of iron, calcium, and magnesium, and about 2 to 5% by weight of entrapped water. When…