Grease resistance testing is used to measure the repellence of paper and board materials to grease, oil and waxes.
All the tests described below should be used only as a guide to performance and not a substitute for tests with prototype end products containing the actual product oils or greases.
The Kit Test (Tappi T559)
The Kit test measures the degree of repellence or anti-wicking of paper and boards which have been treated with fluorochemical sizing agents used to prevent wetting of the cellulose fibres of the material. Test solutions with varying strengths of castor oil, toluene, heptane and turpentine are used. The highest numbered solution (the most aggressive) that remains on the surface of the paper without causing failure is reported as the "kit rating" (maximum 12).
The Kit test is used to quantify or compare the performance of papers and boards, used for food contact and other packaging applications where resistance to grease staining is important.
Smithers Pira testing is performed to the Tappi standard T559.
Turpentine Test (Tappi T454)
Silica sand is placed on the paper and dyed turpentine added to saturate the sand. The time taken for the dye to penetrate the paper is determined.
This test is usually applied to greaseproof, glassine, vegetable parchment. It is not always suitable for assessing papers and boards that are given grease or oil resistance by means of a coating or internal treatment.
Smithers Pira testing is performed to the Tappi standard T454 and MOD Def standard 81-93/2 Annex A.
Permeability Test (ISO 16532-1)
The grease resistance of both creased and uncreased paper and board is determined as the time taken for a simulated "fat material" (palm kernel oil) to penetrate the board coating.
This test method has the advantage that it is equally applicable to paper and board that has been internally or surface sized with organophobic materials, or plastic coated.
Smithers Pira testing is performed to BS ISO 16532-1.