Substantially rigid thermally insulating panel and method for manufacturing it

A substantially rigid thermally insulating panel (1) which consists of at least two substantially flexible composite sheets (2) spaced apart by a great number of flexible strands (3) arranged so that in the inflated state the two composite sheets (2) are held apart and in predetermined positions one with respect to the other, each composite sheet (2) comprising, from the center toward the outside:

• a protective internal sheet (4), transparent to electromagnetic waves, especially infrared waves,
• a thin sheet (5) of a metal reflecting electromagnetic waves,
• a layer (6) for protecting the metal sheet,
• a fibrous layer (7) providing the sheet with mechanical strength,
• a layer (8) of a coating polymer providing proofing,
• a layer (9) for protecting an underlying metal sheet,
• a thin sheet (10) of a metal reflecting electromagnetic waves, and
• a protective outer layer (11) transparent to electromagnetic waves, by virtue of all of which, after the empty space (12) separating the two composite sheets (2) and through which a great/number of flexible strands (3) pass is inflated under pressure, a thermally insulating rigid panel with very high efficiency is formed.