In today’s folding carton landscape, the choice of raw materials can be daunting. Substitutions are sometimes made with little or no regard to suitability; nonetheless, the differences in paperboard properties and appropriate applications are creating some interesting nuances in today’s tight board market. The choice of substrate is influenced by a number of key parameters, including the requirements of print performance, product protection, design features and requirements, sustainability and overall value.
Solid Bleached Sulfate (SBS)
In North America, Solid Bleached Sulfate (SBS) is a prominent packaging material. Made from mostly hardwood, first-generation, chemically pulped fibers are subsequently bleached, refined and formed in one ply on fourdrinier-type paperboard machines. SBS is white on both sides and throughout the sheet. The relatively short hardwood fibers are coated and polished, creating an impressively smooth print surface that accommodates the highest quality imaging by offset, flexography and gravure.
SBS generally performs well for embossing, hot foil stamping, creasing, and gluing. It cuts cleanly and has sufficient internal and surface strength properties to accommodate high-speed printing with tacky oil-based lithographic inks. SBS is not known for tear strength, but generally has good stiffness and compression strength. Other properties like being hygienic and pure with no smell and taste, make it usable for flavour sensitive products like cigarettes, Pharmaceutical, chocolate, and cosmetics. SBS is often higher priced as compared with other paperboard substrates.
Primary North American suppliers of SBS include International Paper (IP-Everest), Westrock (Printkote), Georgia Pacific (GP-Masterprint) and Clearwater (Candesce).
Folding Box Board (FBB, TMP)
Folding box board also referred as FBB, CTMP or TMP comprises middle layers of mechanical pulp sandwiched between outer layers of chemical pulp. The top layer of chemical pulp is bleached and pigment coated. The back of the paperboard is cream (manila) in colour. This is because the back layer of bleached or unbleached chemical pulp is translucent, allowing the colour of the middle layers to influence the appearance.
Being virgin fibre paperboard with consistent purity for product safety, the combination of inner layers of mechanical pulp with outer layers of chemical pulp creates a strong and stiff sheet, making it a low density material with high stiffness. The fully coated grades give great printing and visual impact.
Primary European and Asian suppliers of FBB include, Rayonier (Tembec-Kallima), Metsä Board (Pro FBB Bright); Stora Enso (Tambrite) and APP (Zenith).
Coated Recycled board (CRB, CCNB, CCWB, Duplex, LWC…)
Coated Recycled Board (CRB), aka CCNB (clay-coated newsback) is a dominant product worldwide. CRB is generally made from a blend of recycled, newsprint, old corrugated containers and mixed secondary paper. Its fibers are often 100 percent recycled, with 35 percent or more of the content considered “post-consumer.” It is comprised of as many as eight or more layers of material, with the top ply made of bleached or semi-bleached fibers. A variety of machines is used in its manufacture, including fourdrinier, cylinder and hybrid forming systems.
CRB is the most common substrate for low-cost folding cartons when recycled content is preferred or required. It is for multi-purpose packaging where tear strength and premium print quality aren’t paramount. It often has a one direction stiffness advantage
Primary North American suppliers of CRB include Graphic Packaging, Westrock, and Paperworks.
Solid Unbleached Sulfate (SUS)
Clay natural kraft (CNK) or solid unbleached sulfate (SUS) is a superior strength and tear resistance paperboard grade that is produced from a furnish containing at least 80 percent virgin unbleached, natural wood pulp. It is formed in two or three layers and is mostly comprised of longer softwood (pine) fibers which contribute to strength. A thin concentration of hardwood fibers is added to the top surface for somewhat enhanced smoothness. It is white on the top side due to its extremely opaque, titanium-based coating to improve its printing surface.
Its natural resistance to moisture make it an ideal candidate for refrigerated and frozen applications.
Primary North American suppliers of SUS include Graphic Packaging and Westrock.
UNK Uncoated natural kraft (KraftPak)
Uncoated Kraft Boxboard (UKB) or Uncoated Natural Kraft, commonly known as Kraftpak (Kapstone Brand) is formed on a fourdrinier-type paperboard machine in two layers, where the top layer houses a concentration of hardwood fiber for somewhat enhanced smoothness.
It is a strong, lightweight, uncoated and unbleached kraft paperboard grade, designed to provide maximum strength, cleanliness and performance while using the least amount of fiber. The quality of graphic reproduction doesn’t match that of coated materials; however, designers are sometimes creative with the earth-tone appearance.
A primary North American supplier of Kraftpak is Kapstone Charleston Kraft (acquired recentely by Westrock)
Coated Kraft Back (CKB)
European Coated Kraft Back (CKB) is gaining a foothold in the North American folding carton market. Because of tougher competition, North American end users want to reduce packaging costs, while maintaining the high quality of their packs. This situation has given CKB a competitive edge, as its structure allows the use of a 15-20% lower grammage without compromising stiffness properties.
The board is manufactured in five layers. The middle CTMP layer gives the board excellent stiffness properties, thanks to which the packer can use board of a lower grammage. The top layer is double blade coated, which ensures good printability. In addition, the board is chemically and microbiologically pure and thus suitable for all consumer packs.
CKB is an ideal packaging material for folding cartons of dry, chilled and frozen food, chocolate, wine and spirits. CKB also makes great multipacks – the eye-catching pack is light and strong and is easy to buy, carry, open and recycle.
Primary North American suppliers of CKB include Stora Enso and Smurfit Kappa.
Uncoated recycled board (URB, Bending Chip, Chipboard)
Uncoated Recycled Paperboard (URB) is made from 100% recycled fibres. Commonly known as “Chipboard,”. Chipboard has a smooth, uncoated surface on both sides and the color varies depending on the recycled fibers used.
Primary North American suppliers of URB include Cascades, White Birch, Caraustar, Westrock and Sonoco.
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Photo Source: Zumbiel Packaging