Process for the preparation of hydroxyl-functionalized polyether-polysiloxane block copolymers

A method for producing a hydroxyl-functionalized polyether-polysiloxane block copolymer, said method comprising the steps of:

• providing a compound having the general Formula (IA)
• wherein:
• q is an integer of from 5 to 250;
• r is an integer from 2 to 4;
• n is 0;
• m is 1;
• R1 is selected from hydrogen and a C1-C6 alkyl group;
• A denotes a spacer group comprising a covalent bond or a C1-C12 alkylene group;
• Ra, Rb, Rc, Rd, R2, R3, R4 and R5 may be the same or different and each is independently selected from hydrogen, a C1-C8 alkyl group, a C6-C18 aryl group or a C6-C18 aralkyl group, with the proviso that R2, R3, and R5 are hydrogen and R4 is either a phenyl group or a C1-C8 alkyl group;
• and
• R6, R7, R8, R9, and R10 may be the same or different and each is independently selected from a hydrogen atom, a C1-C8 alkyl group, a C3-C10 cycloalkyl group, a C6-C18 aryl group or a C6-C18 aralkyl group;
• providing a double metal cyanide complex catalyst;
• preheating a mixture of the compound and the double metal cyanide complex catalyst to a first temperature and maintaining the first temperature for a period of time;
• providing at least one alkylene oxide monomer having the general Formula (II):
• wherein:
• R2, R3, R4 and R5 may be the same or different and are independently selected from hydrogen, a C1-C8 alkyl group, a C6-C18 aryl group or a C6-C18 aralkyl group, with the proviso that at least one of R3 and R4 is not hydrogen;
• and
• performing a ring opening polymerization of the at least one alkylene oxide monomer of general Formula (II) in the presence of the compound of Formula (IA) and the double metal cyanide complex catalyst to provide the hydroxyl-functionalized polyether-polysiloxane block copolymer,
• wherein providing the at least one alkylene oxide monomer is a semi-batch process that comprises:
• 1) heating the mixture of the compound and the double cyanide complex catalyst to a second temperature higher than the first temperature;
• 2) adding a first portion of the at least one alkylene oxide monomer to the mixture of the compound and the double metal cyanide complex catalyst at the second temperature;
• and
• 3) after activation of the double metal cyanide complex catalyst as indicated by an equilibrium pressure in the semi-batch process, continuously dosing the mixture with a second portion of the at least one alkylene oxide monomer.