Process for preparing and optionally chain extending aqueous polyisocyanate dispersions using static mixers

Claim 2

A process for preparing an aqueous, polyisocyanate dispersion which has an isocyanate content of at least 0.5% by weight, based on the weight of the polyisocyanate, and is prepared by a process which comprises a) introducing an aqueous medium into an inlet of a static mixer, b) introducing a polyisocyanate which has an isocyanate content of at least 12% by weight into the same or a different inlet of said static mixer, c) mixing said polyisocyanate with said aqueous medium in said static mixer, d) withdrawing said aqueous polyisocyanate dispersion from the outlet of said static mixer, e) introducing said aqueous polyisocyanate dispersion into the inlet of a second static mixer, f) introducing into the same or a different inlet of said second static mixer a chain extender containing at least one of i) a primary or secondary monoamine containing at least one hydroxyl group in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0.1:1.0 to 0.7:1.0 and ii) a polyamine having primary and/or secondary amino groups and a molecular weight of 400 or less in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0.1:1.0 to 0.4:1.0, provided that when components i) and ii) are both mixed with the dispersed polyisocyanate, the equivalent ratio of amino groups from both components i) and ii) to isocyanate groups does not exceed 0.95:1.0, g) mixing said chain extender with said aqueous polyisocyanate dispersion in said second static mixer, h) withdrawing the reacting mixture of said aqueous polyisocyanate dispersion and said chain extender from the outlet of said second static mixer and i) forming a film of the reacting mixture while the NCO content is at least 0.5% by weight.

Claim 3

The process of claim 1 wherein said dispersed polyisocyanate is rendered hydrophilic by reaction with a compound containing a lateral or terminal nonionic hydrophilic group.

Claim 4

The process of claim 1 wherein said chain extender comprises a primary or secondary monoamine which corresponds to the formula ##STR3## wherein R 1 represents hydrogen or an alkyl, cycloalkyl, araliphatic or aromatic group having up to 15 carbon atoms, R 2 is an optionally branched alkylene group containing 1 to 12 carbon atoms, m represents 0 or 1, n represents 1 or 2 and m+n=2.

Claim 5

The process of claim 3 wherein R 1 is an alkyl group containing 1 to 6 carbon atoms and R 2 is an optionally branched alkylene group containing 1 to 4 carbon atoms.

Claim 6

A process for preparing an aqueous, polyisocyanate dispersion which has a functionality of at least 2 and an isocyanate content of at least 1.0% by weight, based on the weight of the polyisocyanate, and is prepared by a process which comprises a) introducing an aqueous medium into an inlet of a static mixer, b) introducing into the same or a different inlet of said static mixer a polyisocyanate which has an isocyanate content of at least 12% by weight and is rendered hydrophilic by reaction with a compound containing a lateral or terminal nonionic hydrophilic groups, c) mixing said polyisocyanate with said aqueous medium in said static mixer, d) withdrawing said aqueous polyisocyanate dispersion from the outlet of said static mixer, e) introducing said aqueous polyisocyanate dispersion into the inlet of a second static mixer, f) introducing into the same or a different inlet of said second static mixer a chain extender containing at least one of i) a primary or secondary monoamine containing at least one hydroxyl group in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0.1:1.0 to 0.7:1.0 and ii) a polyamine having primary and/or secondary amino groups and a molecular weight of 400 or less in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0.1:1.0 to 0.4:1.0, provided that when components i) and ii) are both mixed with the dispersed polyisocyanate, the equivalent ratio of amino groups from both components i) and ii) to isocyanate groups does not exceed 0.95:1.0, g) mixing said chain extender with said aqueous polyisocyanate dispersion in said second static mixer, h) withdrawing the reacting mixture of said aqueous polyisocyanate dispersion and said chain extender from the outlet of said second static mixer and i) forming a film of the reacting mixture while the NCO content is at least 1.0% by weight.

Claim 7

A process for preparing an aqueous, polyisocyanate dispersion which has a functionality of at least 2 and an isocyanate content of at least 1.0% by weight, based on the weight of the polyisocyanate, and is prepared by a process which comprises a) introducing an aqueous medium into an inlet of a static mixer, b) introducing into the same or a different inlet of said static mixer a polyisocyanate which has an isocyanate content of at least 12% by weight and is rendered hydrophilic by reaction with a compound containing a lateral or terminal nonionic hydrophilic groups, c) mixing said polyisocyanate with said aqueous medium in said static mixer, d) withdrawing said aqueous polyisocyanate dispersion from the outlet of said static mixer, e) introducing said aqueous polyisocyanate dispersion into the inlet of a second static mixer, f) introducing into the same or a different inlet of said second static mixer a chain extender containing at least one of i) a primary or secondary monoamine containing at least one hydroxyl group in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0.1:1.0 to 0.7:1.0 and ii) a polyamine having primary and/or secondary amino groups and a molecular weight of 400 or less in an amount sufficient to provide an equivalent ratio of amino groups to isocyanate groups of 0.1:1.0 to 0.4:1.0, provided that when components i) and ii) are both mixed with the dispersed polyisocyanate, the equivalent ratio of amino groups from both components i) and ii) to isocyanate groups does not exceed 0.95:1.0, g) mixing said chain extender with said aqueous polyisocyanate dispersion in said second static mixer, h) withdrawing the reacting mixture of said aqueous polyisocyanate dispersion and said chain extender from the outlet of said second static mixer and i) forming a film of the reacting mixture while the NCO content is at least 1.0% by weight.

Claim 8

The process of claim 5 wherein said chain extender comprises a primary or secondary monoamine which corresponds to the formula ##STR4## wherein R 1 represents hydrogen or an alkyl, cycloalkyl, araliphatic or aromatic group having up to 15 carbon atoms, R 2 is an optionally branched alkylene group containing 1 to 12 carbon atoms, m represents 0 or 1, n represents 1 or 2 and m+n=2.

Claim 9

The process of claim 6 wherein R 1 is an alkyl group containing 1 to 6 carbon atoms and R 2 is an optionally branched alkylene group containing 1 to 4 carbon atoms.