"More specifically, hydroxyl groups (--OH) on the surface of the hydrated metal compound and silanol groups ???Si--OH) of the silane-grafted polymer cause a hydrolytic condensation reaction to form strong siloxane linkages [--Si--O--Mm On (M is a metal)], under the influences of (a) a small amount of water present on the surface of the hydrated metal compound and (b) the hydrated metal compound whi" . . . .