Polyurea product as modifying agent thixotropic rheology.

thixotropic agent comprising a first reaction product polyurea of ​​a first polyisocyanate with a first amine and a second reaction product polyurea of ​​a second polyisocyanate with a second amine different from the first reaction product polyurea, and wherein the second polyurea reaction product has been precipitated in the presence of colloidal particles of the first reaction product.