Patent ID: 8334357

Claim:
A thickener based on an aqueous preparation of nonionic, water-dispersible or water-soluble polyurethane, wherein the polyurethane is obtained, through the formation of an allophanate intermediate, by the reaction of: (a) one or more hydrophilic polyols which contain per molecule at least two OH groups and at least two functional groups selected from the group consisting of —O— (ether groups) and —COO— (ester groups), the molecular weight of the hydrophilic compounds being at least 300; (b) one or more hydrophobic compounds containing at least one zerewitinoff-active hydrogen atom per molecule, the molecular weight of the hydrophobic compounds ranging from about 100 to about 500 with at least one linear or branched, saturated or unsaturated alkyl chain per molecule, wherein the compound comprises 6 to 24 carbon atoms per molecule and the alkyl chain comprises at least five consecutively linked carbon atoms not linked to a heteroatom; and (c) one or more at least difunctional isocyanates, wherein components (a), (b) and (c) are reacted with one another in equivalent ratios of OH a) :ZH b) :NCO c) of 1:(1+x):2(1+y), wherein OH a) is the primary (terminal) OH groups of component (a), ZH b) is the NCO-reactive functional group containing the zerewitinoff-active hydrogen atom of component (b), and NCO c) is the isocyanate group of component (c), with the provisos that x is a number of 0.05 to 1.2 and y is a number of (0.2 to 1.05)x , and the ratio of NCO c) equivalents to the sum of OH a) equivalents and ZH b ) equivalents is greater than 1 to 1.