Insulating sheet, and backrest seat and cold weather garment employing the same

A heat insulating sheet comprising:

• a first sheet having a main surface;
• a first heat insulator disposed on the main surface of the first sheet, the first heat insulator including a first xerogel;
• a second heat insulator disposed on the main surface of the first sheet apart from the first heat insulator, the second heat insulator including a second xerogel;
• a second sheet disposed on the main surface of the first sheet to cover the first heat insulator and the second heat insulator;
• a third heat insulator disposed on the main surface of the first sheet apart from the first heat insulator and the second heat insulator, the third heat insulator including a third xerogel;
• and
• a fourth heat insulator disposed on the main surface of the first sheet apart from the first heat insulator, the second heat insulator, and the third heat insulator, the fourth heat insulator including a fourth xerogel,
• wherein the second sheet is disposed on the main surface of the first sheet to cover the first heat insulator, the second heat insulator, the third heat insulator, and the fourth heat insulator,
• wherein the first heat insulator has a rectangular shape when viewed in a direction perpendicular to the main surface of the first sheet,
• wherein the second heat insulator has a rectangular shape when viewed in the direction perpendicular to the main surface of the first sheet,
• wherein the third heat insulator has a rectangular shape when viewed in the direction perpendicular to the main surface of the first sheet,
• wherein the fourth heat insulator has a rectangular shape when viewed in the direction perpendicular to the main surface of the first sheet,
• wherein a first region of the heat insulating sheet provided between one side of the rectangular shape of the first heat insulator and one side of the rectangular shape of the second heat insulator viewing in the direction perpendicular to the main surface has an extensible rate larger than an extensible rate of each of the first heat insulator and the second heat insulator,
• wherein a second region of the heat insulating sheet provided between one side of the rectangular shape of the third heat insulator and one side of the rectangular shape of the fourth heat insulator viewing in the direction perpendicular to the main surface has an extensible rate larger than an extensible rate of each of the third heat insulator and the fourth heat insulator,
• wherein a third region of the heat insulating sheet provided between another side of the rectangular shape of the first heat insulator and another side of the rectangular shape of the third heat insulator viewing in the direction perpendicular to the main surface has an extensible rate larger than an extensible rate of each of the first heat insulator and the third heat insulator,
• wherein a fourth region of the heat insulating sheet provided between another side of the rectangular shape of the second heat insulator and another side of the rectangular shape of the fourth heat insulator viewing in the direction perpendicular to the main surface has an extensible rate larger than an extensible rate of each of the second heat insulator and the fourth heat insulator,
• wherein the first sheet is joined to the second sheet in the first region, the second region, the third region, and the fourth region,
• wherein a first slit, a second slit, a third slit, and a fourth slit which pass through the first sheet and the second sheet are provided in the first region, the second region, the third region, and the fourth region, respectively, an entirety of the first slit, an entirety of the second slit, an entirety of the third slit, and an entirety of the fourth slit being disposed within the first region, the second region, the third region, and the fourth region, respectively, and
• wherein no hole passing through the first sheet and the second sheet is provided in a region which is located between the first region and the second region and between the third region and the fourth region.