Prepolymers based on di- or polyisocyanates and formamide-terminated low molecular weight compounds, processes for preparing the same and uses thereof

1. A prepolymer of the general formula (II):

X—[—N(CHO)—CO—NH—R 1 —NCO] n   (II)

wherein X represents a linear or branched aliphatic, cycloaliphatic, heterocyclic and/or aromatic structural unit having 2 to 20 carbon atoms, which is free of polyether structural units and which is optionally further substituted and/or optionally comprises one or more heteroatoms; wherein R 1 represents an organic radical which may optionally contain one or more heteroatoms and which may further contain one or more additional free isocyanate groups and/or one or more urethane, biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione and/or uretdione structural units; and wherein n≧2.

2. The prepolymer according to claim 1 , wherein R 1 represents an aliphatic hydrocarbon radical having 4 to 36 carbon atoms, a cycloaliphatic hydrocarbon radical having 6 to 15 carbon atoms, an aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbon atoms which may optionally contain one or more heteroatoms and which may further contain one or more additional free isocyanate groups and/or one or more urethane, biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione and/or uretdione structural units.

3. The prepolymer according to claim 1 , wherein X represents a structural unit derived from a polyamine X(NH 2 ) n , wherein n≧2, selected from the group consisting of ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butanediamine, neopentanediamine, 1,5-diamino-2-methylpentane, 2-butyl-2-ethyl-1,5-pentanediamine, 1,6-hexamethylenediamine, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or 2,4,4-trimethyl-1,6-diaminohexane, 1,8-diaminooctane, 1,11-diaminoundecane, 1,12-diaminododecane, 4-aminomethyl-1,8-octanediamine (triaminononane), diethylenetriamine, triethylenetetramine, 1-amino-3,3,5-trimethyl-5-aminomethyl-cyclohexane, TCD-diamine, 1,4-cyclohexanediamine, 2,4- and/or 2,6-hexahydrotoluoylenediamine, isopropyl-2,4-diaminocyclohexane and/or isopropyl-2,6-diaminocyclohexane, tricyclodecanebis(methylamine), 1,3-bis-(aminomethyl)-cyclohexane, 2,4′- and/or 4,4′-diaminodicyclohexylmethane, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, isomeric diaminodicyclohexylmethanes containing a methyl group as a substituent on the nucleus, 3(4)-aminomethyl-1-methylcyclohexyl-amine, 1,3-diaminobenzene, 1,4-diaminobenzene, 2,4- and 2,6-diaminotoluene, 1,3-bis-(aminomethyl)-benzene, 3,5-diethyltoluene-2,4-diamine, m-xylylenediamine, 4,6-dimethyl-1,3-benzenedimethanamine, 4,4′- and/or 2,4′- and/or 2,2′-methylenebisbenzenamine, dimer fatty acid diamines, bis-(3-aminopropyl)-methylamine, 4,9-dioxadodecane-1,12-diamine, 4,7,10-trioxamidecane-1,13-diamine, diamines containing alkoxysilane groups and Michael adducts prepared by reaction of bifunctional primary amines with compounds containing unsaturated groups.

4. A process for preparing a prepolymer of the general formula (II):

X—[—N(CHO)—CO—NH—R 1 —NCO] n   (II)

the process comprising providing a di- or polyisocyanate, providing a formamide-terminated low molecular weight compound, and reacting the di- or polyisocyanate with the formamide-terminated low molecular weight compound; wherein X represents a linear or branched aliphatic, cycloaliphatic, heterocyclic and/or aromatic structural unit having 2 to 20 carbon atoms, which is free of polyether structural units and which is optionally further substituted and/or optionally comprises one or more heteroatoms; wherein R 1 represents an organic radical which may optionally contain one or more heteroatoms and which may further contain one or more additional free isocyanate groups and/or one or more urethane, biuret, carbodiimide, isocyanurate, allophanate, iminooxadiazinedione and/or uretdione structural units; and wherein n≧2.

5. The process according to claim 4 , wherein the process further comprises separating excess di- or polyisocyanate from the prepolymer.

6. The process according to claim 4 , wherein the formamide-terminated low molecular weight compound has the general formula (III):

X—[—NH(CHO)] n   (III)

wherein X and n are as defined, and wherein one mole of the formamide-terminated low molecular weight compound is reacted with n to 10(n) moles of the di- or polyisocyanate.

7. The process according to claim 6 , wherein the process further comprises separating excess di- or polyisocyanate from the prepolymer.

8. A composition comprising a prepolymer according to claim 1 and one or more additional components selected from adhesive, lacquer, and sealant reactants, auxiliaries and additives.

9. A method for preparing a composition selected from the group consisting of adhesives, lacquers, and sealants, the method comprising providing a prepolymer according to claim 1 , and reacting or blending the prepolymer with one or more additional components selected from adhesive, lacquer, and sealant reactants, auxiliaries and additives.