Claims
- 1. A composition comprising:
at least one reaction product of polyols with a stoichiometric excess of mixtures of asymmetrical polyisocyanates having a molecular weight below 500 and an NCO functionality from 1.75 to 2.5 and high molecular weight polyisocyanates.
- 2. The composition of claim 1, wherein the high molecular weight polyisocyanates are reaction products of diols having an average molecular weight from 60 to 2000 with monomeric diisocyanates having a molecular weight of less than 500.
- 3. The composition of claim 2, wherein the high molecular weight polyisocyanates contain less than 10% by weight of monomeric diisocyanate.
- 4. The composition of claim 1, wherein the asymmetrical diisocyanate is at least one of aromatic diisocyanate, aliphatic diisocyanate, cycloaliphatic diisocyanates, tolylene diisocyanate, naphthalene 1,5-diisocyanate, naphthalene 1,4-diisocyanate, diphenylmethane 2,4′-diisocyanate, mixtures of 4,4′-diphenylmethane diisocyanate with the 2,4′-MDI isomer, 1,3-phenylene diisocyanate, 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane, 1,4-diisocyanato-2,2,6-trimethylcyclohexane, 1-methyl-2,4-diisocyanatocyclohexane, 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, or lysine diisocyanate.
- 5. The composition of claim 1, wherein the asymmetrical diisocyanate is diphenylmethane 2,4′-diisocyanate having a 4,4′-MDI and 2,2′-MDI content of less than 10%.
- 6. The composition of claim 1, wherein the asymmetrical diisocyanate is diphenylmethane 2,4′-diisocyanate having a 4,4′-MDI and 2,2′-MDI content of less than and preferably less than 2.5%.
- 7. The composition of claim 1, wherein the diols having a molecular weight from 60 to 2000 are selected from the group consisting of C2- to C18-alkanediols, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-methylpropanediol, 1,6-hexanediol, 2,4,4-trimethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polyoxytetramethylene glycol having a molecular weight of up to 650, alkoxylation products of bisphenol A, alkoxylation products of bisphenol F, isomeric dihydroxyanthracenes, isomeric dihydroxynaphthalenes, pyrocatechol, resorcinol, and hydroquinone having up to 8 alkoxy units per aromatic hydroxyl group, or mixtures thereof.
- 8. The composition of claim 1, wherein the polyol is selected from the group consisting of di- or trifunctional polyethylene glycols, polypropylene glycols, random or block copolymers of ethylene oxide and propylene oxide, poly(oxytetramethylene) glycols, polyesterpolyols, poly-ε-caprolactones, hydroxyl-functional polybutadienes or hydrogenation products thereof, and hydroxyl-functional poly(meth)acrylates, or mixtures thereof.
- 9. The composition of claim 1, wherein the polyol has a number average molar mass of 400 to 20000.
- 10. The composition of claim 1, wherein the polyol has a number average molar mass of 1 000 to 6000.
- 11. A method for preparing polyurethane prepolymers, comprising:
reacting asymmetrical polyisocyanate with polyols in an NCO:OH ratio between 0.25 and 1.8:1; and thereafter, adding high molecular weight polyisocyanate.
- 12. The method of claim 11, wherein the high molecular weight polyisocyanate is added in stoichiometric excess.
- 13. The method of claim 11, further comprising adding heat or a catalyst.
- 14. The method of claim 11, wherein the OH:NCO ratio in the step of adding is 0.4 to 0.7:1.
- 15. The method of claim 11, wherein the method is carried out at temperatures between 40° C. and 130° C.
- 16. The method of claim 11, wherein the method is carried out at temperatures between 60° C. and 110° C.
- 17. The method of claim 11, wherein the step of reacting is carried out at temperatures between 40° C. and 80° C.
- 18. A reactive one- or two-component adhesive/sealant comprising the composition of claim 1.
- 19. A reactive hotmelt adhesive comprising the composition of claim 1.
- 20. A laminating adhesive comprising the composition of claim 1.
- 21. The laminating adhesive of claim 20 wherein the adhesive is solventless.
- 22. An assembly foam comprising the composition of claim 1.
- 23. A potting compound comprising the composition of claim 1.
- 24. A foam comprising the composition of claim 1.
- 25. The foam of claim 24, wherein the foam is a rigid foam, a flexible foam, or a structural foam.
Priority Claims (1)
Number |
Date |
Country |
Kind |
101 63 857.4 |
Dec 2001 |
DE |
|
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of PCT/EP02/14223, filed Dec. 13, 2002, which claims the benefit of DE 101 63 857.4, filed Dec. 22, 2001, the complete disclosures of which are hereby incorporated by reference in their entirety.
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/EP02/14223 |
Dec 2002 |
US |
Child |
10873884 |
Jun 2004 |
US |