PURPOSE: To raise the dielectric constant of a humidity sensible film, and to improve the sensitivity by forming the humidity sensible film by using a high polymer consisting essentially of cellulose acetate dienephthalate.
CONSTITUTION: A humidity sensible film 3 is formed by a humidity sensible material consisting essentially of cellulose acetate hydrodienephthalate especially, in a cellulose high polymer material. As for an adsorption site of water, there are two parts at a rational formula, and its sorption moisture quantity increases, comparing with that of cellulose acetate butyrate CAB, since the hydrophilic property is strong. That is, a variation characteristic of a dielectric constant of the CAHP to the relative humidity becomes larger than a variation characteristic of a dielectric constant of the CAB, and in such a way, the variation characteristic of an electric capacity value to its relative humidity becomes larger in the humidity sensible film formed by using the CAHP than the humidity sensible film formed by using the CAB.
SADAOKA YOSHIHIKO
KUROIWA TAKAO
MIYAGISHI TETSUYA
