Patent ID: 7752776

Claim:
A method of insulating a boot comprising providing a boot having a toe cap area, a boot upper and a boot sole; providing a mixture comprising a porous material selected from fumed metal oxide and aerogel; compressing the mixture to form a structure material, placing more than one section of the structure material in a gas impermeable envelope, evacuating air from the envelope at reduced pressure, and sealing the envelope, to form a flat insulating structure comprising more than one section of structure material within the envelope; sealing the envelope between sections of the structure material within the envelope to provide flexibility to the flat insulating structure for shaping; shaping the flat insulating structure from a flat structure into the form of a shaped insulating structure; and inserting the shaped insulating structure into the boot, the shaped insulating structure having a thermal conductivity of less than or equal to 25 mW/m K at 25° C.