Paperboard Mills

SIC 2631

NAICS 322130

The world's paperboard mills manufacture paperboard, often known in lay terms as cardboard, for various purposes using wood pulp and other fiber pulp. Certain paperboard mills also manufacture converted paperboard products. For discussion of converted paperboard as used in containers, see also Paperboard Containers and Boxes. A general treatment of paperboard's source material, pulp, is given under Pulp Mills, and for information about paper manufacturers, see also Paper Mills.

INDUSTRY SNAPSHOT

Paperboard production is usually considered a part of the paper industry. Paperboard is defined as any thick, heavyweight paper product. The distinction between paper and paperboard is based on product thickness. While all sheets above 0.3 mm can be classified as paperboard, enough exceptions are applied in the trade to make that definition hazy. For the most part, paperboard is made in the same manner as paper.

In some countries, such as the United States, total paperboard production is equal to or exceeds paper production. In other areas, such as Europe, paper production still exceeds paperboard production by a wide margin. Statistics for these two areas are frequently combined in reports.

Most paperboard is used to make materials for corrugated boxes, and the growth of the global paperboard industry is directly linked to the use of paperboard boxes (commonly called cardboard boxes). Prior to the acceptance of corrugated containers for shipping, wooden crates and boxes were used.

Worldwide production capacity grew steadily after the mid-1990s, but began slowing in 2000. Most paperboard is consumed in its country of origin, but paperboard also is a major export product for many countries. In 2003, according to the Food and Agricultural Service of the United Nations (FAO), the world produced 290.2 mmt of paper and paperboard.

ORGANIZATION AND STRUCTURE

Two grades of paperboard—corrugating medium and linerboard—are used to make corrugated shipping containers. (Corrugating medium is called "fluting" in Europe and other regions.) Those two grades, together known as containerboard, account for the majority of paperboard produced around the world. A third grade—solid bleached sulfate (SBS), also called solid bleached board (SBB)—is used to make folding cartons, such as those used in retail stores. SBS accounts for a large share of the remaining production.

One major distinction among paperboard grades is their classification as folding or non-folding grades. Folding grades must be flexible enough that the surface will not split or crack when the board is folded to make a box.

Most paperboard can be classified as follows:

•Boxboard: board of various compositions used to make folding boxboard and set-up or rigid boxes;

•Foodboard: single or multi-ply paperboard used for food and liquid packaging; or

•Containerboard: board for containers consisting of two or more linerboard grades separated by corrugating medium glued to the liners.

The classification of paperboard usually depends on how it is used. Folding boxboard, for example, is made to permit folding without breaking the surface, while at the same time providing good surface finish and the ability to be used in a wide variety of carton shapes. The bending property is not as important in set-up boxes, which instead require board that can be easily scored (depressed or partially cut). For foodboard, special surface treatments are usually needed to provide water and/or grease resistance. Similarly, liquid packaging grades usually require an additional conversion process in which plastic and/or foil lamination takes place to make the container impermeable to air and water.

The U.S. Department of Labor's OSHA division classifies the following as primarily shipping paperboard or paperboard products: binders' board; bottle cap board; boxboard; bristols, bogus; cardboard; clipboard (paperboard); clay coated board; container board; folding boxboards; leatherboard; liner board, kraft, and jute; manila lined board; matrix board; milk carton board; newsboard; paperboard mills, except building board mills; paperboard, except building board; patent coated paperboard; pressboard; setup boxboard; shoe board; special food board; stencil board; strawboard, except building board; tagboard; and wet machine board.

Packaging is the single largest application for paperboard in most countries. Some countries, such as the United States, tend to use more virgin materials to manufacture paperboard, while others, such as South Korea, use more recycled fiber in their production process. The use of recycled fiber in paperboard production is growing fast, however, particularly in the United States. Most recycled fiber is used in products in which the reclaimed pulp does not need to be cleaned. Cereal cartons, for example, are typically made from a product called combination boxboard, with two white outside layers suitable for printing covering a gray, recycled inner layer. Kraft softwood (made from coniferous trees such as pine) has been the preferred pulp for making paperboard because of its strength. Most paperboard is unbleached (brown), but bleached (white) grades are used where appearance is important, such as for retail packaging.

Corrugated containers are, by far, the dominant global means of packaging goods for shipment. Converting plants, located in every industrialized country, use corrugating medium and linerboard to make boxes. Typically, these converting plants are located in urban areas, close to container users. While there are a large number of independent box converters (also called boxmakers), many box-converting plants are owned by the same companies that manufacture the linerboard and medium.

The two main raw materials used to make corrugating medium are semichemical hardwood pulp and recycled pulp (typically old corrugated containers that have been used and discarded). Hardwood pulp is made from deciduous trees such as oak and maple. The pulp from these trees has short, inflexible fibers that help make the corrugating medium stiff. This, combined with their lower cost in comparison to softwood fibers (from coniferous trees such as pine), make them the fiber of choice for medium. The term semichemical designates that the pulp used to make medium is only partially "cooked" in the digester and is partially washed, so it retains much of the glue-like lignin that hold the fibers together in the wood. With the lignin and other wood by-products remaining in the corrugating medium, it is easier to form a rigid fluted shape with a corrugating machine.

Use of recycled pulp in boxboard varies by country. For example, Asian countries, which often lack resources for virgin pulp, use a high percentage of recycled pulp to make boxboard. The United States, on the other hand, has traditionally used mostly virgin pulp. However, that equation is changing rapidly. Semichemical medium's share of total U.S. medium production declined to about 59 percent in 1996, from 72 percent in 1992 and 79 percent in 1980. The share of recycled medium production grew to 28 percent in 1992 and to 41 percent in 1996.

Medium, like other grades of paper and paperboard, is categorized by "basis weights." The higher the basis weight, the heavier the paper or board. National standards for medium differ, but typical basis weights are 22-, 26-, 33-, 36-, and 40-pound. The standard U.S. weight is 26-pound, which accounted for the majority of all production in the late 1990s and early 2000s.

Medium production is directly related to worldwide production of corrugated boxes, measured as "shipments." After several weak years in the early 1990s, corrugated box shipments accelerated rapidly in 1994...

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