Curable composition

A curable composition comprising (A) a reactive silicon group-containing polyether polymer and (B) dibutyltin diacetylacetonate as a silanol condensation catalyst,

• said (A) reactive silicon group-containing polyether polymer having a partial structure of the following general formula (1) per molecule:
• —O—R1—CH(CH3)—CH2—(Si(R22−b)(Xb)O)mSi(R33−a)Xa (1)
• wherein R1 represents a divalent organic group containing 1 to 20 carbon atoms and one or more constituent atoms selected from the group consisting of hydrogen, oxygen and nitrogen;
• R2 and R3 may be the same or different and each represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or a triorganosiloxy group of the formula (R′)3SiO—;
• when 2 or more R2 or R3 groups are present, they may be the same or different;
• R′ represents a monovalent hydrocarbon group containing 1 to 20 carbon atoms and three R′ groups may be the same or different;
• X represents a hydroxyl group or a hydrolyzable group and when two or more X groups are present, they may be the same or different;
• a represents 0, 1, 2 or 3;
• b represents 0, 1 or 2;
• b may be the same or different over m repeats of (Si(R22−b)(Xb)O);
• m represents an integer of 0 to 19:
• provided that the relation of a+Σb ≧1 is satisfied, and wherein not less than 85% of the number of molecular chain terminals have the reactive silicon groups as determined by NMR analysis in said (A) reactive silicon group-containing polyether polymer.