TYPES OF PAPERBOARD

Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.30 mm, 0.012 in, or 12 points) than paper and has certain superior attributes such as foldability and rigidity. According to ISO（The International Organization for Standardization） standards, paperboard is a paper with a grammage above 250 g/m2, but there are exceptions. Paperboard can be single- or multi-ply.

SBB: Solid bleached board

Solid bleached board is made exclusively from bleached chemical pulp. It usually has a mineral pigment coated top surface and some grades are also coated on the back. The term SBS (solid bleached sulphate), derived from the method of pulp production, is sometimes used to describe this product. This paperboard has excellent surface and printing characteristics. It gives wide scope for innovative structural design and can be embossed, cut, creased, folded and glued with ease.

SUB: Solid unbleached board

Solid unbleached board is made exclusively from unbleached chemical pulp (Fig. 8.7). The base board is brown in color. This product is also known as solid unbleached sulphate. To achieve a white surface, it can be coated with a white mineral pigment coating, sometimes in combination with a layer of bleached white fiber under the coating. This board is used where there is a high strength requirement in terms of puncture and tear resistance and/or good wet strength is required, such as for bottle or can multipacks, and as a base for liquid packaging.

FBB: Folding box board

Folding boxboard comprises middle layers of mechanical pulp sandwiched between layers of bleached chemical pulp. The top layer of bleached chemical pulp is Usually coated with a white mineral pigment coating. The back is cream (manilla) in color. This is because the back layer of bleached chemical pulp is translucent allowing the color of the middle layers to show through.

CUK: COATED UNBLEACHED KRAFT

Whereas SBS is white throughout, CUK is made from unbleached virgin kraft fiber, which imparts a natural brown color. This board grade is comprised primarily of various southern pine species (softwoods) with some hardwood fiber, particularly in the top ply which is clay-coated to create a smooth, white printing surface. The long, large pine fibers impart excellent strength and tear resistance qualities to the finished sheet. This strength characterizes the CUK grade. It’s commonly used for beer and soft drink beverage containers as well as heavy-duty retail packaging such as hardware and concentrated laundry detergents.