GB/T 26203-2023 "Paper and board — Determination of internal bond strength (Scott type)" is applicable to single-layer and multi-layer paper and board, including coated paper and paper and board with polymer film on the surface. It is not applicable to handmade paper, or paper and board with low basis weight, high porosity, softness, or low density. The standard defines the terminology for internal bond strength and specifies two test methods for determining the average potential energy required to delaminate a sample through a sandwich structure test. It standardizes the requirements for test instruments, sample preparation, and result presentation, including precision requirements and instrument compliance verification.