Patent ID: 7537002

Claim:
An exothermic agent comprising, per mass thereof, more than 30% but not more than 40% of a calcium oxide powder having an average particle size of 75 μm to 150 μm, and not less than 60% but less than 70% of a mixed aluminum powder in which (a) an aluminum powder having such a particle size distribution that a particle size of 45 μm pass is 70.0 to 80.0% and a particle size of 45 to 75 μm is 20.0 to 30.0% and (b) an aluminum powder having such a particle size distribution that a particle size of 45 μm pass is 60 to 70%, a particle size of 45 μm is 20 to 30%, a particle size of 63 μm is 7 to 10% and a particle size of 75 μm is 1.0 to 2.0% are mixed at a mass ratio of 1:2.