Patent ID: 9534810
Date: 2017-01-03
CPC Classifications: A61F,F24V

Claim:
1. A heating element, comprising: (a) an exothermic layer containing an oxidizable metal, a water absorption agent and water; and (b) a water-retention layer having a first water absorption sheet and a second water absorption sheet, and said exothermic layer is interposed between said first water absorption sheet and said second water absorption sheet, wherein said exothermic layer and said water-retention layer are in layers, wherein a first mass ratio of the content of said water absorption agent is from 0.3 to 20 parts by mass for 100 parts by mass of the oxidizable metal, wherein a second mass ratio of the content of water to the content of said water absorption agent in said exothermic layer (water/water absorption agent) is from 0.8 to 13, and wherein the content of water in said water-retention layer is from 10 to 45 mass % of the maximum water absorption of said water-retention layer.