Grease resistance of paper or board with the KIT test

This test follows the TAPPI Test Method T559. It assesses how fluorochemicals, or other surface treatment chemicals, which can make paper both resistant to oil (organophobic) and water (hydrophobic), affect the paper's surface. These chemicals work by lowering the surface energy of the paper. The test was designed to help papermakers determine if the surface treatment has been successful.

The testing process involves applying a range of numbered mixtures to the paper. The mixtures are prepared using castor oil, n-heptane, and toluene as described in the TAPPI T559 standard. These reagents differ in surface tension and viscosity, or their "aggressiveness," and are numbered from 1 (least aggressive) to 12 (most aggressive).

A drop of the test liquid is dropped on the paper, and after 15 seconds the drop is wiped off. If the paper is darkened by the oil (i.e. the oil has penetrated the paper), the test is considered as failed and a lower KIT mixture is tested.

The test identifies the highest numbered solution that does not leave a stain on the paper. This number is then reported as the paper's "KIT rating."

The result will be given as the number of the first KIT liquid that passes this evaluation.