Polyurethane/polyisocyanurate foam having improved adhesion properties
View Patent ↗A polyurethane/polyisocyanurate foam is obtainable from the reaction of A) a polyol component comprising A1) an aromatic polyester polyol, A2) a polyether polyol started on a carbohydrate polyol and A3) a polyether polyol started on ethylene glycol, wherein the total hydroxyl number of the polyol component A) is from ≧150 mg KOH/g to ≦300 mg KOH/g; with B) a polyisocyanate component, wherein the equivalent ratio of NCO groups to the sum of the hydrogen atoms reactive towards NCO groups is from ≧110:100 to ≦200:100. This foam has improved adhesion properties to facings and is suitable for the production of composite elements without requiring the use of an additional adhesion promoter.
1. A polyurethane/polyisocyanurate foam obtained from the reaction of
A) a polyol component comprising
A1) an aromatic polyester polyol,
A2) a polyether polyol started on a carbohydrate polyol, and
A3) a polyether polyol started on ethylene glycol,
wherein the total hydroxyl number of the polyol component A) is from ≧150 mg KOH/g to ≦300 mg KOH/g;
with
B) a polyisocyanate component,
wherein the equivalent ratio of NCO groups to the sum of the hydrogen atoms reactive towards NCO groups is from ≧110:100 to≦200:100
and components A1) and A3) are present in a weight ratio of from<=4:1 to<=8:1 relative to one another and
wherein in the polyol component A), components A1) and A2) are present in a weight ratio of from ≧1:1 to ≦3:1 relative to one another and/or components A2) and A3) are present in a weight ratio of from ≧2:1 to ≦4:1 relative to one another.
2. The foam according to claim 1 , wherein the aromatic polyester polyol A1) is obtained from phthalic anhydride and diethylene glycol.
3. The foam according to claim 1 , wherein the polyether polyol A3) started on ethylene glycol is obtained from components comprising ethylene glycol and ethylene oxide.
4. The foam according to claim 1 , wherein the polyisocyanate component B) comprises a mixture of diphenylmethane-4,4′-diisocyanate with isomers and higher-functional homologues.
5. A composite element comprising a facing and a layer comprising the polyurethane/polyisocyanurate foam according to claim 1 .
6. The composite element according to claim 5 , wherein no adhesion promoter layer is arranged between the layer comprising the polyurethane/polyisocyanurate foam and the facing.
7. The composite element according to claim 5 , wherein the facing is a metal layer.
8. A process for the production of a composite element, comprising applying a reaction mixture that yields the polyurethane/polyisocyanurate foam according to claim 1 to a facing.
9. The process according to claim 8 , wherein no adhesion promoter layer is arranged between the reaction mixture and the facing.
10. The process according to claim 8 , wherein the facing is a metal layer.
11. The process according to claim 8 , wherein the process is in the form of a twin-belt conveyor process.
12. The process according to claim 8 , wherein the facing has a temperature of from≧40° C. to≦60° C. on application of the reaction mixture.
13. The foam according to claim 2 , wherein the polyether polyol A3) started on ethylene glycol is obtained from components comprising ethylene glycol and ethylene oxide.
14. The foam according to claim 13 , wherein the polyisocyanate component B) comprises a mixture of diphenylmethane-4,4′-diisocyanate with isomers and higher-functional homologues.
15. A composite element comprising a facing and a layer comprising the polyurethane/polyisocyanurate foam according to claim 14 .
16. The process according to claim 8 , wherein the facing has a temperature of from≧50° C. to≦55° C. on application of the reaction mixture.
17. The foam according to claim 14 , wherein the total hydroxyl number of the polyol component A1) is from≧200 mg KOH/g to≦300 mg KOH/g, total hydroxyl number of the polyol component A2) is from≧400 mg KOH/g to≦450 mg KOH/g, and the total hydroxyl number of the polyol component A3) is from≧200 mg KOH/g to ≦300 mg KOH/g.
18. The foam according to claim 14 , wherein the total hydroxyl number of the polyol component A1) is from≧220 mg KOH/g to≦260 mg KOH/g, total hydroxyl number of the polyol component A2) is from≧420 mg KOH/g to≦440 mg KOH/g, and the total hydroxyl number of the polyol component A3) is from≧260 mg KOH/g to≦300 mg KOH/g.
19. The foam according to claim 1 , wherein the polyether polyol A2) started on a sorbitol and is obtained from components comprising sorbitol, glycerol and propylene oxide.
20. A polyurethane/polyisocyanurate foam obtained from the reaction of
A) a polyol component comprising
A1) an aromatic polyester polyol,
A2) a polyether polyol started on a carbohydrate polyol, and
A3) a polyether polyol started on ethylene glycol,
wherein the total hydroxyl number of the polyol component A) is from≧150 mg KOH/g to≦300 mg KOH/g;
with
B) a polyisocyanate component,
wherein the equivalent ratio of NCO groups to the sum of the hydrogen atoms reactive towards NCO groups is from≧110:100 to≦200:100
and components A1) and A3) are present in a weight ratio of from≧=4:1 to≦=8:1 relative to one another and
the total hydroxyl number of the polyol component A1) is from≧200 mg KOH/g to≦300 mg KOH/g, total hydroxyl number of the polyol component A2) is from≧400 mg KOH/g to ≦450 mg KOH/g, and the total hydroxyl number of the polyol component A3) is from≧200 mg KOH/g to≦300 mg KOH/g.
21. The foam according to claim 20 , wherein the total hydroxyl number of the polyol component A1) is from≧220 mg KOH/g to≦260 mg KOH/g, total hydroxyl number of the polyol component A2) is from≧420 mg KOH/g to≦440 mg KOH/g, and the total hydroxyl number of the polyol component A3) is from≧260 mg KOH/g to≦300 mg KOH/g.