Polyurethane gelling agent

A process for preparing a polyurethane compound of formula (I)

• A1 is a linear alkyl radical, comprising 2 to 12 carbon atoms, said radical optionally comprising one or more unsaturations;
• A2 is
• l and m are, independently of one another, an integer from 1 to 20, the sum of l+m being from 2 to 20;
• n is an integer from 2 to 8;
• D is a linear or branched alkyl radical, comprising from 6 to 14 carbon atoms, said radical optionally comprising one or more unsaturations;
• X is a linear or branched C2-C10 alkyl radical, having or not having unsaturations;
• Y is an oxygen an atom,
• the process comprising the following steps:
• 1) functionalizing a di-OH estolide of formula (3) by a diisocyanate derivative of formula (4) in order to obtain a diisocyanate estolide of formula (5)
• A1, A2, l and m are as defined above;
• X is a linear or branched C2-C10 alkyl radical, having or not having unsaturations;
• 2) performing a chain extension in order to obtain a polyurethane of estolide of formula (7) by adding a diol of formula (6), optionally solubilized in an oil
• wherein
• A1, A2, E, X, Y, l and m are as defined above;
• D is a linear or branched alkyl radical, comprising 6 to 14 carbon atoms, said radical optionally comprising one or more unsaturations;
• n is an integer from 2 to 12;
• and
• 3) optionally, performing chain termination by adding a nucleophilic molecule in excess capable of reacting with the residual isocyanate functions in order to give the gelling polyurethane of formula (I).