PURPOSE: To obtain the silane compsn. having an excellent coupling effect and UV absorption effect in combination by constituting the compsn. of the reaction product of a water soluble solvent, the salt of diaminostilbene sulfonic acid and org. polyamine and a specific silane compd.

CONSTITUTION: The UV absorptive silane compsn. is constituted of the reaction product of the water soluble solvent, the salt of the diaminostilbene sulfonic acid and the org. polyamine, and the silane compd. expressed by the general formula I. In the formula, X denotes a halogen atom, epoxy group, isocyanate group or acrylic group; R1 denotes a bivalent hydrocarbon group or substd. hydrocarbon group which may be interrupted by an oxygen atom or nitrogen atom; R2 denotes a lower alkyl group; R3 denotes a hydrogen atom or lower alkyl group; n is 0 or 1. This silane compsn. has high reactivity with a synthetic resin or glass surface and has the excellent UV absorbing effect. Substrates, fiber reinforced resins, etc., having the high adhesiveness with synthetic resins and inorg. materials and the excellent UV absorbability are, therefore, obtainable.