The TAPPI T 559 standard specifies a method for determining the grease resistance of paper and Cardboard. Grease resistance refers to the ability of a material to resist the penetration of grease and is an important performance indicator for evaluating its use in applications such as food Encasement, grease product Encasement, etc. The standard describes in detail the testing equipment, reagents, sample preparation, testing procedures and methods for evaluating results. By using standard grease and specific pressure conditions, the ability of a sample to resist the penetration of grease for a certain period of time is tested, and the penetration time or degree of penetration is used as the evaluation basis. The standard is applicable to all types of paper and Cardboard, especially for materials such as food Encasement paper and grease-proof paper that require grease resistance performance.