PURPOSE: To provide an alkoxysilane functionalized acrylic polymer composition which comprises a specific alkoxysilane functionalized acrylic polymer, a reactive silanol solution and a silane crosslinker and which is low in price, and has excellent weather resistance, excellent heat resistance or the like, and is useful for a sealing agent, an adhesive or the like.

CONSTITUTION: This composition comprises (A) an alkoxysilane functionalized acrylic polymer which is a free radical polymerization product derived from (i) 90 to 99 wt.% of at least one acrylate or methacrylate monomer (preferably, ethyl acrylate), (ii) 2 to 4 wt.% of at least one vinyl addition monomer having an alkoxysilane moiety, (iii) at least one other vinyl addition monomer comprising an aromatic compound substituted with a vinyl group or the like, and a solvent, preferably toluene or the like, (B) 5 to 15% of a reactive silanol solution which is a liquid mixture comprising a polyfunctional silane crosslinker, a hydroxy terminated siloxane polymer and a non-reactive silicone polymer, and (C) a silane crosslinker (preferably, methyloxysilane or the like).