Improvements in or relating to vitreous materials

摘要

To increase the thermal insulating properties of a vitreous material of closed cellular structure, the material while still in a molten state is subjected to pressure or stretching or a combination of the two forces in mutually perpendicular directions, whereby the cells become compressed or stretched or both, the height of the cells in the deformed material being reduced to a relatively considerable extent with respect to their original form. Deformation may be such that the cells resemble hollow fibres. The deformed material may be further treated, to roughen at least one surface, by placing the material while still plastic in contact with granular material, such as sand, of higher melting point so that the granular material becomes embedded on the surface. Tiles or bricks of the material can then be more easily cemented to other surfaces.