| abstract |
The content of compound(s) having a molecular weight of 650-670, preferably a molecular weight of 660, as measured by mass spectrometry, is reduced to 0.5 mass% or less in a heat-sensitive recording material comprising 3,3'-diallyl-4,4'-dihydroxy diphenylsulfone, or in a diphenylsulfone or a color-developing agent. Provided is, thereby, a heat-sensitive recording material, a color-developing agent, or a diphenylsulfone which cause less background fogging under moisture and heat conditions and which has excellent preservation stability of a colored image. |