Isocyanate-terminated prepolymers based on polyoxymethylene-polyoxyalkylene block copolymers, process for the preparation and use thereof
The present invention relates to isocyanate-terminated prepolymers based on polyoxymethylene-polyoxyalkylene block copolymers, to a process for their preparation, and to the use of these isocyanate-terminated prepolymers as isocyanate components in 1- and 2-component systems for coatings, adhesives and sealants.
1 . A process for preparing an isocyanate-terminated prepolymer comprising reacting:
A) at least one polyisocyanate, wherein component A) has an NCO content according to DIN EN ISO 11909:2007-05 of 15% to 60% by weight;
B) at least one polyoxymethylene-polyoxyalkylene block copolymer having a hydroxyl number according to DIN 53240-2:2007-11 of 15 mg KOH/g to 200 mg KOH/g;
C)i) at least one amino-containing polyether based on propylene oxide having a hydroxyl number according to DIN 53240-2:2007-11 of 40 to 80 mg KOH/g, an OH functionality of 4.0 and an amine content according to DIN EN 9702:1998 in the range from 0.5% to 1.0% by weight;
C)ii) optionally at least one amino-containing polyether based on based on ethylene oxide, propylene oxide or a mixture of ethylene oxide and propylene oxide having an NH 2 -functionality of 2 or 3, which is different from C) i) the at least one amino-containing polyether; and
D) optionally auxiliaries (D2) containing protic acids and/or auxiliaries (D1) which are not protic acids.
2 . The process of claim 1 , wherein component B) consists of a polyoxymethylene-polypropylene oxide block copolymer or a polyoxymethylene-polyoxyalkylene carbonate block copolymer.
3 . The process of claim 1 , wherein at least component B) has been prepared in the presence of a double metal cyanide catalyst, and component B) contains at least some of the double metal cyanide catalyst, wherein the content of double metal cyanide catalyst based on the total amount of components B) and C) is 10 to 5000 ppm determined using the amount of metal content from the double metal cyanide catalyst determined according to DIN ISO 17025, August 2025.
4 . The process of claim 1 , wherein the at least one polyoxymethylene-polyoxyalkylene block copolymer of component B) has a hydroxyl number according to DIN 53240-2:2007-11 of 15 mg KOH/g to 150 mg KOH/g.
5 . The process of claim 1 , wherein the at least one amino-containing polyether of component C)i) has a hydroxyl number according to DIN 53240-2:2007-11 of 45 to 75 mg KOH/g.
6 . The process of claim 1 , wherein the at least one amino-containing polyether of component C)i) has an amine content according to DIN EN 9702:1998 of 0.56% to 0.94% by weight.
7 . The process of claim 1 , wherein component A) comprises at least one aromatic polyisocyanate.
8 . The process of claim 1 , wherein the isocyanate-terminated prepolymer is a reaction product of a composition comprising:
50% to 70% by weight of component A),
15% to 30% by weight of component B),
10% to 30% by weight of component C)i),
0% to 15% by weight of component C)ii),
0.10% to 0.20% by weight of component D1), and
0% to 0.50% by weight of component D2),
wherein all % by weight values are based on the sum of all components of the composition.
9 . An isocyanate-terminated prepolymer obtained by the process of claim 1 .
10 . The process of claim 2 , wherein the polyoxymethylene-polypropylene oxide block copolymer and/or the polyoxymethylene-polyoxyalkylene carbonate block copolymer comprises two terminal polyoxyalkylene blocks.
11 . The process of claim 7 , wherein the at least one aromatic polyisocyanate comprises 1,5-naphthalene diisocyanate, diisocyanatodiphenylmethane, poly(methylene phenyl isocyanate), diisocyanatomethylbenzene, or a mixture thereof.
12 . An isocyanate-terminated prepolymer comprising a reaction product of a composition comprising:
A) at least one polyisocyanate, wherein component A) has an NCO content according to DIN EN ISO 11909:2007-05 of 15% to 60% by weight;
B) at least one polyoxymethylene-polyoxyalkylene block copolymer having a hydroxyl number according to DIN 53240-2:2007-11 of 15 mg KOH/g to 200 mg KOH/g;
C)i) at least one amino-containing polyether based on propylene oxide having a hydroxyl number according to DIN 53240-2:2007-11 of 40 to 80 mg KOH/g, an OH functionality of 4.0 and an amine content according to DIN EN 9702:1998 in the range from 0.5% to 1.0% by weight;
C)ii) optionally at least one amino-containing polyether based on based on ethylene oxide, propylene oxide or a mixture of ethylene oxide and propylene oxide having an NH 2 -functionality of 2 or 3, with the exception of amino-containing polyethers of component C)i); and
D) optionally auxiliaries containing protic acids (D2) and/or auxiliaries which are not protic acids of D2 (D1).
13 . The isocyanate-terminated prepolymer of claim 12 , wherein the composition comprises:
50% to 70% by weight of component A),
15% to 30% by weight of component B),
10% to 30% by weight of component C)i),
0% to 15% by weight of component C)ii),
0.10% to 0.20% by weight of component D1), and
0% to 0.50% by weight of component D2),
wherein all % by weight values are based on the sum of all components of the composition.
14 . A paint, adhesive or sealant system comprising the isocyanate-terminated prepolymer of claim 12 .
15 . The paint, adhesive or sealant system of claim 14 , wherein the paint, adhesive or sealant system is a 1-component moisture-curable system comprising no isocyanate-reactive components in addition to components C)i) and C)ii).
16 . The paint, adhesive or sealant system of claim 14 , wherein the paint, adhesive or sealant system is a 2-component moisture-curable system comprising at least one isocyanate-reactive component in addition to components C)i) and C)ii).
17 . A substrate coated or bonded with the paint, adhesive or sealant system of claim 14 .