Isocyanate mixture and its use as binder in one-component lacquers

Claim 2

An isocyanate mixture suitable for use as a binder for one-component lacquers, which mixture is stable in storage in the absence of moisture and is cross-linked by moisture with the formation of urea groups and has a solvent-free viscosity measured in a DIN cup 4 according to DIN 53 211 of from about 30 to 200 seconds and contains a maximum of about 0.7% by weight of readily volatile organic diisocyanates, comprising a mixture of: (a) at least one lacquer polyisocyanate containing biuret, urethane and/or isocyanurate groups and having an average isocyanate functionality greater than 2 and an isocyanate content of from about 13 to 30% by weight and (b) at least one monoisocyanate corresponding to the following general formula: R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having from 1 to 18 carbon atoms optionally interrupted by ether bridges and R 2 represents a group such as is obtained by removal of the isocyanate groups from an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of from about 140 to 300, the proportion by weight of component (a) to component (b) being from about 2:1 to 5:1, and the average isocyanate functionality of the mixture being greater than about 1.8.

Claim 3

A process of coating a substrate comprising (1) applying a lacquer composition containing as a binder an isocyanate mixture having an isocyanate functionality greater than 1.8, a solvent-free viscosity of between about 30 and 200 seconds in a DIN cup 4 according to DIN 53 211 and a volatile diisocyanate content of less than about 0.7 wt % to said substrate, said mixture comprised of (a) an organic polyisocyanate having an average isocyanate functionality greater than 2, containing urethane, biuret and/or isocyanurate groups and having an isocyanate content of between about 13 and 30 wt %, and (b) a monoisocyanate of the general formula: R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having 1 to 18 carbon atoms and optionally interrupted by ether bridges, and R 2 represents the isocyanate free residue of an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of between about 140 and 300, said components mixed in a ratio of a:b of from about 2:1 to 5:1, (2) exposing said substrate to atmospheric moisture for a sufficient time to cause the isocyanate groups of said mixture to react with the moisture and form a cured coating.

Claim 4

A process of coating a substrate comprising (1) applying a lacquer composition containing as a binder an isocyanate mixture having an isocyanate functionality greater than 1.8, a solvent-free viscosity of between about 30 and 200 seconds in a DIN cup 4 according to DIN 53 211 and a volatile diisocyanate content of less than about 0.7 wt % to said substrate, said mixture comprised of (a) an organic polyisocyanate having an average isocyanate functionality greater than 2, containing urethane, biuret and/or isocyanurate groups and having an isocyanate content of between about 13 and 30 wt %, and (b) a monoisocyanate of the general formula: R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having 1 to 18 carbon atoms and optionally interrupted by ether bridges, and R 2 represents the isocyanate free residue of an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of between about 140 and 300, said components mixed in a ratio of a:b of from about 2:1 to 5:1, (2) exposing said substrate to atmospheric moisture for a sufficient time to cause the isocyanate groups of said mixture to react with the moisture and form a cured coating.

Claim 5

The isocyanate mixture of claim 1 wherein the polyisocyanate is an adduct of hexamethylene diisocyanate.

Claim 6

The isocyanate mixture of claim 1 wherein the monoisocyanate is an adduct of hexamethylene diisocyanate or toluene diisocyanate.

Claim 7

In a process for the preparation of one-component lacquers which can be hardened by the action of moisture, the improvement comprising using the isocyanate mixture of claim 1 as a binder.

Claim 8

An isocyanate mixture suitable for use as a binder for one-component lacquers, which mixture is stable in storage in the absence of moisture and is cross-linked by moisture with the formation of urea groups and has a solvent-free viscosity measured in a DIN cup 4 according to DIN 53 211 of from about 30 to 200 seconds and contains a maximum of about 0.7% by weight of readily volatile organic diisocyanates, consisting essentially of a mixture of: (a) at least one lacquer polyisocyanate containing biuret, urethane and/or isocyanurate groups and having an average isocyanate functionality greater than 2 and an isocyanate content of from about 13 to 30% by weight and (b) at least one monoisocyanate corresponding to the following general formula: R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having from 1 to 18 carbon atoms optionally interrupted by ether bridges and R 2 represents a group such as is obtained by removal of the isocyanate groups from an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of from about 140 to 300, the proportion by weight of component (a) to component (b) being from about 2:1 to 5:1 and the average isocyanate functionality of the mixture being greater than about 1.8.

Claim 9

An isocyanate mixture suitable for use as a binder for one-component lacquers, which mixture is stable in storage in the absence of moisture and is cross-linked by moisture with the formation of urea groups and has a solvent-free viscosity measured in a DIN cup 4 according to DIN 53 211 of from about 30 to 200 seconds and contains a maximum of about 0.7% by weight of readily volatile organic diisocyanates, consisting essentially of a mixture of: (a) at least one lacquer polyisocyanate containing biuret, urethane and/or isocyanurate groups and having an average isocyanate functionality greater than 2 and an isocyanate content of from about 13 to 30% by weight and (b) at least one monoisocyanate corresponding to the following general formula: R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having from 1 to 18 carbon atoms optionally interrupted by ether bridges and R 2 represents a group such as is obtained by removal of the isocyanate groups from an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of from about 140 to 300, the proportion by weight of component (a) to component (b) being from about 2:1 to 5:1 and the average isocyanate functionality of the mixture being greater than about 1.8.

Claim 10

A process of coating a substrate comprising (1) applying a lacquer composition containing as a binder an isocyanate mixture having an isocyanate functionality greater than 1.8, a solvent-free viscosity of between about 30 and 200 seconds in a DIN cup 4 according to DIN 53 211 and a volatile diisocyanate content of less than about 0.7 wt.% to said substrate, said mixture consisting essentially of (a) an organic polyisocyanate having an average isocyanate functionality greater than 2, containing urethane, biuret and/or isocyanurate groups having an isocyanate content of between about 13 and 30 wt.%, and (b) a monoisocyanate of the general formula R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having 1 to 18 carbon atoms and optionally interrupted by ether bridges, and R 2 represents the isocyanate free residue of an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of between about 140 and 300, said components mixed in a ratio of a:b of from about 2:1 to 5:1, (2) exposing said substrate to atmospheric moisture for a sufficient time to cause the isocyanate groups of said mixture to react with the moisture and form a cured coating.

Claim 11

A process of coating a substrate comprising (1) applying a lacquer composition containing as a binder an isocyanate mixture having an isocyanate functionality greater than 1.8, a solvent-free viscosity of between about 30 and 200 seconds in a DIN cup 4 according to DIN 53 211 and a volatile diisocyanate content of less than about 0.7 wt.% to said substrate, said mixture consisting essentially of (a) an organic polyisocyanate having an average isocyanate functionality greater than 2, containing urethane, biuret and/or isocyanurate groups having an isocyanate content of between about 13 and 30 wt.%, and (b) a monoisocyanate of the general formula R.sub.1 --O--CO--NH--R.sub.2 --NCO wherein R 1 represents a hydrocarbon group having 1 to 18 carbon atoms and optionally interrupted by ether bridges, and R 2 represents the isocyanate free residue of an aliphatic, cycloaliphatic, araliphatic or aromatic diisocyanate having a molecular weight of between about 140 and 300, said components mixed in a ratio of a:b of from about 2:1 to 5:1, (2) exposing said substrate to atmospheric moisture for a sufficient time to cause the isocyanate groups of said mixture to react with the moisture and form a cured coating.