Two-part organopolysiloxane composition

A two-part organopolysiloxane composition comprising first and second parts wherein the composition cures after the first and second parts are mixed together,

• said first part comprising
• (A) 50 to 190 parts by weight of an organopolysiloxane having the general formula (1):
• HO(SiR12O)nH (1)
• wherein R1 is each independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms, and n is an integer of at least 10,
• (B) 0.1 to 20 parts by weight of at least one compound selected from the group consisting of a ketene silyl acetal compound having the general formula (2), a 2-methyldialkoxysilylpropionic ester having the general formula (3), and partial hydrolyzates thereof,
• (R2O)2Si(R3)OC(OR3)CHCH3 (2)
• (R2O)2Si(CH3)CH(CH3)COOR3 (3)
• wherein R2 is an alkyl group of 1 to 4 carbon atoms, R3 is a substituted or unsubstituted alkyl group of 1 to 12 carbon atoms, R2 and R3 may be the same or different,
• (C) 0.01 to 20 parts by weight of an organic compound having at least one nitrogen atom in the molecule and/or a silane compound having at least one nitrogen atom in the molecule,
• (D) 0.1 to 30 parts by weight of a silane compound having at least two alkoxy groups in the molecule, represented by the general formula (4), or a partial hydrolytic condensate thereof,
• R5mSi(OR4)4-m (4)
• wherein R4 is an unsubstituted or alkoxy-substituted monovalent hydrocarbon group of 1 to 4 carbon atoms, R5 is a substituted or unsubstituted monovalent hydrocarbon group of 1 to 10 carbon atoms, and m is 0, 1 or 2, and
• (E) 0.1 to 10 parts by weight of at least one compound selected from the group consisting of a ketene silyl acetal compound having the general formula (5), a 2-trialkoxysilylpropionic ester having the general formula (6), and partial hydrolyzates thereof,
• (R2O)3SiOC(OR3)CHCH3 (5)
• (R2O)3SiCH(CH3)COOR3 (6)
• wherein R2 and R3 are as defined above,
• said second part comprising
• (F) 150 to 10 parts by weight of an organopolysiloxane having the general formula (7):
• HO(SiR12O)nH (7)
• wherein R1 and n are as defined above,
• (G) 0.01 to 10 parts by weight of an organotin catalyst, and
• (H) 0.1 to 10 parts by weight of water,
• with the proviso that the total amount of components (A) and (F) is 200 parts by weight, and the amounts of components (B) to (E) in the first part and the amounts of components (G) and (H) in the second part are relative to the total amount of components (A) and (F) which is 200 parts by weight.