Patent ID: 8314050

Claim:
A material for pressure measurement comprising a substrate made of plastic, a color forming agent layer containing an colorless electron-donating dye precursor and a color developing agent layer containing an electron-accepting compound, the material for pressure measurement forming a color utilizing a color forming reaction between the colorless electron-donating dye precursor and the electron-accepting compound, wherein the colorless electron-donating dye precursor is included in a microcapsule containing an urethane bond, wherein at least one kind of the electron-accepting compounds is a metal salt of salicylic acid having a substituent, and wherein the microcapsule satisfies the relation δ/D=from 1.0×10 −3 to 2.0×10 −2 , where δ is the number-average wall thickness (μm) of the microcapsules, and D is the median diameter (μm) of the microcapsules on a volume basis.