Top Liner

Top Liner is a professional term in corrugated cardboard production, referring to the outer layer of paperboard laminated to the outermost surface of corrugated cardboard. It is usually kraft linerboard or white top linerboard, used for printing and providing physical strength. In foreign trade, this term is commonly found in orders, contracts, and technical specifications in industries such as paper products, packaging materials, and printing consumables. Usage scenarios include: describing corrugated cardboard structure (e.g., top liner, corrugating medium, back liner), specifying top liner grammage (e.g., 125g/㎡), material (e.g., kraft liner, white top liner), color, and printability. Notes: It is necessary to clarify the difference between top liner and back liner—the top liner faces outward and requires printing effect and bursting strength; the back liner faces inward and emphasizes flatness. Unlike 'facing paper', top liner specifically refers to the outer layer of corrugated cardboard, while facing paper may broadly refer to surface-coated paper. Foreign trade contracts should specify indicators such as basis weight, tightness, and water absorption value of the top liner to avoid disputes caused by standard differences (e.g., US standards vs. European standards). In addition, the quality of the top liner directly affects the compression resistance and moisture resistance of cartons, and should be selected according to the transportation environment.