The Paper Industry: An Overview of Board Types and Manufacturing Process
The paper industry has been a significant part of the global economy for centuries, and its products are ubiquitous in our daily lives. It encompasses a wide range of products, including newspapers, books, packaging, and tissue paper.
The paper industry is divided into two main categories: pulp and paper, and paperboard. While pulp and paper refer to products made from wood fibers, paperboard encompasses thicker and stiffer products that are used for packaging, printing, and other applications.
Types of Boards in the Paper Industry
Carton board is a type of paperboard that is commonly used for packaging various products. It is a stiff and durable material with excellent printing capabilities and barrier properties.
Carton board is made from a variety of grades, including solid board and other grades that
have bending qualities, and is characterized by its stiffness, caliper, bulk, printability, and barrier properties. It can be easily printed on, stamped, shaped, and folded, making it an ideal choice for packaging boxes, especially those that require a high degree of rigidity and protection. Carton board is widely used in the food, beverage, pharmaceutical, and consumer goods industries for a variety of packaging applications.
Solid board is made from a single furnish and is used for various applications. Solid Bleached Surfate (SBS) is traditionally made from bleached chemical pulp, but RCF is being added in recent times. The two types of SBS are uncoated (UZ) and coated (GZ). UZ is used mainly for food board, such as frozen food cartons, cups, plates, and ovenable trays. LPB is used when plastic coated, such as Tetra Pak milk cartons and other dairy products and juice cartons. GZ is used for food board, and a board-based butter tub designed for Carrefour has been marketed in Europe using Stora Enso’s Ensocoat and Ensocup board grades plus Ensobarr coating. The strength of coated unbleached Kraft (CUK) has made it popular as carrier board for beverage multipack carriers, envelopes, and food board. SUK is the uncoated version, and the coating is about 30 g/m2 on one side.
Folding box board (FBB) is a type of paperboard used for packaging, printing, and other applications. It has a furnish with sufficient long fiber to allow creasing without cracking. There are two types of FBB: coated and uncoated.
Coated folding box board includes GC1, GC2, and GC3. GC1 is used for high-quality cartons, such as cosmetics, chocolates, and cigarettes. GC2 is used for lower-quality cartons, such as detergent packs and cereal packages. GC3 has high bulk. Uncoated FBB includes UC1 and UC2, which are used for end-use requiring lower quality.
Duplex board has two furnishes, a base of RCF, and a top liner that may contain virgin pulp or be 100% RCF. The commonest duplex board is white-lined chipboard (WLC). Coated duplex (GD) includes clay-coated news, CCN, and bending news board. Uncoated duplex (UD) consists of a white patent-coated news board, which is not coated. Some duplex boards are not bending quality. Triplex (T) grades have three furnishes: a top liner, filler, and bottom liner. The liners for the chipboard can be white, brown, Kraft, or Manila. The white-lined manila-backed board is GT if coated or UT if uncoated.
Aseptic Packaging
Aseptic packaging is an important aspect of the paper industry, particularly in the production of liquid packaging board (LPB). Aseptic packaging refers to the process of filling and packaging a sterile product in a way that maintains its sterility throughout its shelf life. This is achieved by using a combination of heat treatment and aseptic filling, which sterilizes the product and the packaging separately before they are combined. Aseptic packaging is used for products that require a longer shelf life, such as milk and juice, and is commonly seen in the form of Tetra Pak cartons.
Barrier Properties
Barrier properties are responsible for protecting the contents of a package from external factors such as moisture, oxygen, and light. Different grades of paper and board have varying barrier properties, which makes them suitable for different applications. For example, LPB used for aseptic packaging has high barrier properties to protect the contents from oxygen and light, while frozen food cartons require good moisture and grease
resistance.
Coating is often used to enhance the barrier properties of paper and board. For example, the coated unbleached Kraft (CUK) board is commonly used as carrier board for beverage multipack carriers due to its strength and good barrier properties. Coatings can also be used to improve the printability and appearance of the board.
In addition to barrier properties, other important properties of board grades used for carton production include Scott ply bond, stiffness, caliper, bulk, and printability. Scott ply bond refers to the strength of the board in terms of its ability to resist delamination or splitting, while stiffness is important for ensuring that the carton maintains its shape during transport and handling. Caliper and bulk refer to the thickness and density of the board, respectively, and can affect the weight, cost, and appearance of the carton. Printability is also important for ensuring that the carton can be printed with high-quality graphics and text.
Overall, the paper industry is a complex and important sector that produces a wide range of board grades for different applications, including carton production and aseptic packaging. The properties of these board grades, including their barrier properties, are crucial for
ensuring that the contents of the package are protected and preserved.
Coating and other treatments can be used to enhance these properties, while other factors such as stiffness and printability also play a crucial role in determining the suitability of a board grade for a particular application.
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