Insulating material, electrical heating unit employing same, and manufacturing method therefor

摘要

The present invention is a heat insulating material being a single unit having superior insulating performance as well as sufficient mechanical strength itself to constitute furnace walls, an electric heating unit having the heat insulating material and a method of manufacture of the heat insulating material and the electrical heating unit. The heat insulating material of the present invention includes an outer layer having mainly refractory inorganic fibers and a core layer supported within the outer layer. The outer layer has greater mechanical strength than the core layer. The core layer has a composition having a better insulating performance than the outer layer and extends in a plane substantially perpendicular to the thickness of the heat insulating material. The electrical heating unit of the present invention has a heating element embedded in the heat insulating material.