NCO-modified polyoxymethylene block copolymers

摘要

The invention relates to a method for producing NCO-modified polyoxymethylene block copolymers comprising the step of polymerizing formaldehyde in a reaction vessel in the presence of a catalyst, the polymerization of formaldehyde in addition taking place in the presence of a starter compound comprising at least 2 Zerewitinoff active H atoms to obtain an intermediate product. The intermediate product obtained is reacted further with an isocyanate to obtain an NCO-modified polyoxymethylene block copolymer. The invention also relates to NCO-modified polyoxymethylene block copolymers obtained by a method of this type and to the use of said copolymers for producing polyurethane polymers.

主权项

1. A process for preparing NCO-modified polyoxymethylene block copolymers, comprising the step of polymerizing gaseous formaldehyde in the presence of a catalyst selected from the group consisting of basic catalysts, Lewis-acidic catalysts, and combinations thereof, to form a polyoxymethylene block copolymer intermediate, wherein
the polymerization of formaldehyde is effected in the presence of a starter compound having at least two Zerewitinoff-active hydrogen atoms, giving an intermediate having a number-average molecular weight of <4500 g/mol, and reacting the intermediate with an isocyanate in the presence of a catalyst which is the same catalyst as in the preceding polymerization of formaldehyde, to give an NCO-modified polyoxymethylene block copolymer.