To provide a valve device capable of surely preventing adhesion and capable of surely opening even though a valve body and a valve seat are sometimes kept in a closed valve condition.
The valve seat 3 having an annular valve seat part 31 is formed by PPS resin, and a valve rubber 21 on the valve body 2 side opening and closing by advancing and retreating with respect to the valve seat 3 is formed by fluororubber. Silicon coating is applied on a surface of the valve seat including the valve seat part with the usage of silicone resin as a coating material in order to form a protective film 4. Therefore, hydrogen fluroride sometimes being released from fluororubber is prevented from intruding into PPS resin, and thereby adhesion by molecular bond is prevented.
YOSHIDA AKIRA
KOBARI NAOTO
