A flexible abrasive article includes a unitary backing having first and second opposed major surfaces and comprising a polyurethane. In some embodiments, the backing has an average thickness of from 4 to 6 mils (102 to 152 microns), a tensile strength of 500 to 3200 psi (3.45 to 22.1 MPa), and an ultimate elongation of 230 to 530 percent. In some embodiments, the flexible abrasive article has a tensile strength of 400 to 2400 psi (2.8 to 16.5 MPa), and a ultimate elongation of 180 to 380 percent. An abrasive layer is disposed on and secured to the unitary backing.