Heat generating body, heat insulating method using the same and packaging material for die molding heat generation

A heat generating body wherein a heat generating composition molded body resulting from molding a moldable heat generating composition containing surplus water as a connecting substance is interposed between packaging materials and the periphery of the heat generating composition molded body is heat sealed, characterized in that:

• 1) the packaging materials are each constituted of a substrate and a covering material,
• 2) the substrate, which is substantially planar and does not have an accommodating pocket, has a structure to cover a heat generating composition with the covering material after mounting the heat generating composition on the substantially planar substrate,
• 3) the packaging materials each has a bending resistance of not more than 100 mm,
• 4) the packaging materials are each a non-elastic body at least at a temperature between 25° C. and 60° C., has a breaking strength of 500 g/mm2 or more at 25° C. and has a breaking elongation of 30% or more at 90° C.,
• 5) the moldable heat generating composition contains, as essential components, an iron powder, a carbon component, a reaction accelerator and water, has a water content of from 1 to 60% by weight, does not contain a flocculant aid, a flocculant, an agglomeration aid, a dry binder, a dry binding agent, a dry binding material, a sticky raw material, a thickener and an excipient, contains the surplus water so as to have a water mobility value of from 0.01 to 20, has moldability due to the surplus water, with the water in the moldable heat generating composition not functioning as a barrier layer, and is capable of causing an exothermic reaction upon contact with air,
• 6) plural sectional exothermic parts as divided by a sectioned part which is formed by heat sealing are provided,
• 7) the heat generating body contains a region wherein the ratio of the bending resistance in a first direction orthogonal to the thickness direction of the heat generating body, to the bending resistance in a second direction orthogonal to the thickness direction of the heat generating body and orthogonal to the first direction, is 2 or more,
• 8) at least a part of the heat generating body has permeability to air, and
• 9) the heat generating body has a fixing measure on at least a part of the exposed surface thereof.