Hydrophilic polyisocyanates

A process for preparing a hydrophilic, water-soluble or water-dispersible polyisocyanate, the process comprising reacting:

• A) at least one diisocyanate or polyisocyanate component having an average functionality of 2.0 to 5.0 and having 8% to 27% by weight of aliphatically, cycloaliphatically, araliphatically and/or aromatically attached isocyanate groups (calculated as NCO;
• molecular weight=42);
• with
• B) 0.3% to 25% by weight, based on the total weight of components A) and B), of at least one emulsifier of the formula (1):
• X-[y]-Z (1),
• wherein:
• X represents one or more hydrophilic structural units formed from a substance class X′, where X′ comprises at least one group b) selected from the group consisting of a hydroxyalkylcarboxylic acid, a hydroxyalkylsulphonic acid, a hydroxypolyethersulphonic acid, and a hydroxyalkyl-N,N-dialkylamine of the formula HO—R2NR3R4, wherein R2 R3 and R4 independently represent alkyl groups having 1-18 carbon atoms, said group b) optionally branched or comprising a ring;
• y represents an optional spacer;
• Z represents one or more hydrophobic structural units;
• the emulsifier (B) comprises a functional group which is reactive towards isocyanate groups;
• A) and B) are reacted with one another in an equivalents ratio of NCO groups to functional groups which are reactive towards NCO groups of 2:1 to 400:1;
• the polyisocyanate has an average functionality of 2.0 to 5.0;
• and
• the polyisocyanate comprises 4% to 27% by weight of isocyanate groups, said groups being aliphatically, cycloaliphatically, araliphatically and/or aromaticaly attached isocyanate groups.

A hydrophilic, water-soluble or water-dispersible polyisocyanate, comprising 4% to 27% by weight of isocyanate groups, said groups being aliphatically, cycloaliphatically, araliphatically and/or aromatically attached isocyanate groups,

• wherein the polyisocyanate has an average functionality of 2.0 to 5.0 and is synthesized from:
• A) at least one diisocyanate or polyisocyanate component having an average functionality of 2.0 to 5.0 and having 8% to 27% by weight of aliphatically, cycloaliphatically, araliphatically and/or aromatically attached isocyanate groups (calculated as NCO;
• molecular weight=42);
• and
• B) 0.3% to 25% by weight, based on the total weight of components A) and B), of at least one emulsifier (B) of the formula (1):
• X-[y]-Z (1),
• wherein:
• X represents one or more hydrophilic structural units wherein X comprises polyether radicals and a sulphonic acid group, and Z comprises a hydrocarbon radical having 3 to 18 carbon atoms, and an alcohol group;
• y represents an optional spacer;
• the emulsifier (B) comprises a functional group which is reactive towards isocyanate groups;
• and
• A) and B) are reacted with one another such that an equivalents ratio of NCO groups to functional groups which are reactive towards NCO groups of 2:1 to 400:1.