Flexible Polyurethane Foam

• US 20070232711A1
• Filed: 05/12/2005
• Published: 10/04/2007
• Est. Priority Date: 05/12/2004
• Status: Active Grant

• Current Assignee: Recticel Engineered Foams Switzerland AG (Recticel SA)
• Original Assignee: Fritz HAUG AG
• Inventors: Schoenenberger, Kurt, Frei, Hans, Mispreuve, Henri, Naescher, Reinold
• Granted Patent: US 9,023,907 B2
• Time in Patent Office: Days
• US Class Current: 521/128
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/5045 containing urethane groups
• CPC Class Codes: C08G 18/7621 being toluene diisocyanate including isomer mixtures
• CPC Class Codes: C08G 2110/0008 flexible
• CPC Class Codes: C08G 2110/005 < 50kg/m3
• CPC Class Codes: C08G 2110/0083 prepared using water as the sole blowing agent
• CPC Class Codes: C08J 2205/06 Flexible foams

Abstract

Flexible polyurethane foam is made by mixing prepolymer with foam-forming ingredients comprising isocyanate and water which react to give carbon dioxide. The prepolymer is hydroxyl-tipped, being made by reacting polyol with less than the theoretical proportion of isocyanate required to react with available hydroxyl groups of the polyol. The prepolymer is a new storage stable starting material for use in making flexible polyurethane foam, and the foam produced with the prepolymer has advantageous properties with regard to hydrolysis resistance. The prepolymer may be made with low or high viscosity by appropriate selection of the proportion of isocyanate which reacts with the polyol. At high viscosities cell structure can be advantageously controlled by appropriate gasification or degasification during foaming.

Claims

1. A method of making a flexible polyurethane foam from a mixture of prepolymer and foam-forming ingredients, wherein the prepolymer is made by reacting at least one polyol with at least one multifunctional isocyanate characterised in that the prepolymer is a non-foamed polyol prepolymer having available OH groups, and the foam forming ingredients comprise at least a multifunctional isocyanate and water.

2. A method according to claim 1 characterised in that the polyol which is reacted with the isocyanate to make the prepolymer is at least predominantly a polyether polyol.

3. A method according to claim 1 characterised in that the polyether polyol is at least predominantly propyleneoxide (PO) derived.

4. A method according to claim 3 characterised in that the polyether polyol is a triol.

5. A method according to claim 1 characterised in that the prepolymer is a low viscosity prepolymer made by reacting a proportion in the range 0.1% to 30% by weight of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol.

6. A method according to claim 5 characterised in that the said proportion is in the range 3% to 25%.

7. A method according to claim 1 characterised in that the prepolymer is a high viscosity prepolymer made by reacting a proportion in the range 30% to 99% of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol.

8. A method according to claim 7 characterised in that the said proportion is 30% to 50%.

9. A method according to claim 7 characterised in that the mixture of prepolymer and foam forming ingredients is subjected to gassing or degassing to give a cell structure of predetermined cell count and regularity in the produced polyurethane foam.

10. A method according to claim 1 characterised in that the prepolymer is mixed with the foam forming ingredients in the presence of further polyol or polyols.

11. A method according to claim 10 where the or each further polyol is a polyether polyol.

12. A method according to claim 10 characterised in that the further polyol is the same as that used to react with the isocyanate to make the prepolymer.

13. A method according to claim 1 characterised in that a foam product having a density of 10 to 100, in particular 14 to 70 kg/m³ is produced.

14. A foam product formed by a method according to claim 1 in the form of a flexible foam slab stock.

15. A foam product formed by a method according to claim 1 in the form of a moulded body.

16. A storage stable prepolymer for use in the manufacture of flexible polyurethane foam made by reacting at least one polyol with at least one multifunctional isocyanate characterised in that the proportion of the isocyanate is in the range 0.1% to 99%/o by weight of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol, whereby the prepolymer is tipped with hydroxyl groups available for reaction with further isocyanate.

17. A prepolymer according to claim 16 characterised in that the said proportion is 0.1% to 30%.

18. A prepolymer according to claim 17 characterised in that the said proportion is 3% to 12%.

19. A prepolymer according to claim 16 characterised in that the said proportion is 30% to 99%.

20. A prepolymer according to claim 19 characterised in that the said proportion is 30% to 50%.

21. A prepolymer according to claim 16 characterised in that the polyol is at least predominantly a polyether polyol.

22. A prepolymer according to claim 21 characterised in that the polyether polyol is at least predominantly propyleneoxide derived.

23. A prepolymer according to claim 22 characterised in that the polyether polyol is a triol.

24. A prepolymer according to claim 24 characterised in that it has a viscosity up to 50,000 mPa·

s.

25. A prepolymer according to claim 24 characterised in that the viscosity is up to 35,000 mPa·

s.

26. A prepolymer according to claim 24 characterised in that the viscosity is over 5,000 mPa·

s.

27. A prepolymer according to claim 26 characterised in that the viscosity is over 7,000 mPa·

s.

28. A prepolymer according to claim 24 characterised in that the viscosity is below 20,000 mPa·

s.

29. A prepolymer according to claim 28 characterised in that the viscosity is below 7,000 mPa·

s.

30. A prepolymer according to claim 29 characterised in that the viscosity is below 5,000 mPa·

s.

31. A method of making a flexible polyurethane foam from a mixture of prepolymer and foam-forming ingredients, wherein the prepolymer is made by reacting at least one polyol with at least one multifunctional isocyanate, the prepolymer is a non-foamed polyol prepolymer having a viscosity below 20,000 mPa·

s and having available OH groups made by reacting a proportion in the range 0.1% to 30% by weight of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol, and the foam-forming ingredients comprise at least a multifunctional isocyanate and water.

32. A method according to claim 31 wherein the polyol is at least predominantly a propylene oxide (PO) derived polyether polyol.

33. A method of making a flexible polyurethane foam from a mixture of prepolymer and foam-forming ingredients, wherein the prepolymer is made by reacting at least one polyol with at least one multifunctional isocyanate, the prepolymer is a non-foamed polyol prepolymer having a viscosity in the range 5,000-50,000 mPa·

s and having available OH groups made by reacting a proportion in the range 30% to 99% by weight of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol, and the foam-forming ingredients comprise at least a multifunctional isocyanate and water.

34. A method according to claim 33 wherein the polyol is at least predominantly a propylene oxide (PO) derived polyether polyol.

35. A method of making a flexible polyurethane foam from a mixture of prepolymer and foam-forming ingredients, wherein the prepolymer is made by reacting at least one polyol with at least one multifunctional isocyanate, and prepolymer is a non-foamed polyol prepolymer having a viscosity in the range 15,000-35,000 mPa·

s and having available OH groups made by reacting a proportion in the range 30% to 50% by weight of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol, and the foam-forming ingredients comprise at least a multifunctional isocyanate and water.

36. A method according to claim 35 wherein the polyol is at least predominantly a propylene oxide (PO) derived polyether polyol.

37. A storage stable prepolymer for use in the manufacture of flexible polyurethane foam made by reacting at least one polyol with at least one multifunctional isocyanate characterised in that the proportion of the isocyanate is in the range 0.1% to 99% by weight of the theoretical amount of the isocyanate required to react with all available hydroxyl groups of the polyol, whereby the prepolymer is tipped with hydroxyl groups available for reaction with further isocyanate, and wherein unreacted polyol is incorporated to dilute the prepolymer.