1) Ionic silylated copolyurethane of formula: in which R1 is a hydrocarbon radical; R2 is a C2-C4 alkylene; n is an integer such that the molecular mass of —[OR2]n is 2500-20 000 g/mol; R∘ is H or C1-C18 alkyl; R, R′ and R″ are a hydrocarbon-based radical; x and y are integers from 1 à 8; z is an integer from 0 to 8; m and q are an integer of greater than or equal to 1, such that q/m ranges from 0.04 to 20; F1 is a radical of formula (IIa) and F2 is a radical of formula (IIb): in which R3 is methylene or n-propylene; R4 and R5 are methyl or ethyl; p is equal to 0 or 1; R6 is a C1-C4 alkyl. 2) Process for preparing copolyurethane 1), comprising: (i) polyaddition between a polyisocyanate, a polyether diol and a carboxylic diol; (ii) neutralization of the product formed with the amine N(R)(R′)(R″); then (iii) reaction with an aminosilane derived from a secondary amine. 3) Composition, usable as sealant and/or adhesive, comprising copolyurethane 1) and a filler.