Paperboard

Today paperboard packaging in general, and especially products from certified sustainable sources, are receiving new attention, as manufacturers dealing with environmental, health, and regulatory issues look to renewable resources to meet increasing demand. Sometimes it is referred to as cardboard, which is a generic, lay term used to refer to any heavy paper pulp based board. In 1817, the first paperboard carton was produced in England.

Coatings are usually made up of: Additional components could be OBA (optical brightening agents). Based on the production process and the source of the pulp, different types of paperboard are produced. The common industry abbreviations are: The DIN Standard 19303 Paperboard - Terms and grades (Publication date : 2005-09) defines different grades of paperboard based on the surface treatment (first letter), the main furnish (second letter) and the colour (non-D grade) or bulk (D grade only) (numbering). N = unbleached virgin chemical pulp T = recycled/secondary fibre with white, cream or brown reverse D = recycled/secondary fibre with grey back 1 = white reverse side 2 = cream reverse side 3 = brown reverse side (D grades only): 1 = bulk >= 1.45 cm³/g 2 = bulk < 1.45 cm³/g, > 1.3 cm³/g 3 = bulk <= 1.3 cm³/g Example: GC1 would be a pigment coated , virgin mechanical pulp board with a white reverse side .

Ovenable paperboard was introduced in 1974. Fibrous material is turned into pulp and bleached, to create one or more layers of board, which can be optionally coated for a better surface and/or improved visual appearance. The above mentioned fibrous material can either come from fresh (virgin) sources (e.g. It is now mandatory in many countries for paper-based packaging to be manufactured wholly or partially from recycled material. Mainly two methods for extracting fibres from its source are used: Pulp used in the manufacture of paperboard can be bleached to decrease colour and increase purity.

Other factors which affect board stiffness include thickness, coatings, moisture content, grammage and density. Smoothness: Smoothness is particularly important when being used for printing, the smoother the paperboard, the better the ink coverage. Recycled paperboard may contain traces of inks, bonding agents and other residue which causes a grey colouration.

in North America the top 5 producers have a market share of 85%. . Often the used paperboard type would be FBB, which was coated on both sides. Basis Weight (US): Is the weight of 500 sheets in pounds (mass). Brightness: Brightness is a technical term that is defined as the amount of blue-white light that a paper reflects.

Paperboard used for the manufacture of folding cartons and rigid set-up boxes is often called boxboard. It is measured using air leak methods – the greater the rate of air leakage, at a specific air pressure, from under a cylindrical knife placed on the surface, the rougher the surface. Caliper/Thickness: In the US caliper is usually expressed in thousandths of an inch (0.001”) or points, where a sheet of paperboard with a thickness of 0.024” would be 24 points.

Paperboard can be single or multi-ply. Paperboards used for the manufacture of corrugated fiberboard are called containerboard.

There are three categories of bleaching methods: Multi ply paperboard generally has higher creasing and folding performance than single ply as a result of layering different types of pulp into a single product. It can be easily cut and formed, is lightweight, and is strong used in packaging.

There are various different methods of bleaching, which are used according to a number of factors for example, the degree of colour change required, chemicals chosen and method of treatment. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.25 mm or 10 points) than paper.

Around 90% of virgin paper is made from wood pulp. E.g.

A coated board line with 400kt/y will costs around 60 million Euros (about 85 million USD in 07/2009). Although bleaching is not necessary for all end uses, it is vital for many graphical and packaging purposes.

Paperboard also tends to be referred to with thickness rather than weight. Whiteness: It refers to the equal presence of all colours, because a truly white sheet will reflect all wavelengths of visible light equally. The paperboard sector is mainly looked at in conjunction with the paper industry. The benefits of multi ply paperboard are for example its higher creasing and folding performance. In order to improve whiteness, smoothness and gloss of paperboard, one or more layers of coating is applied.

In Europe it is measured in g/m². Another enduse would be graphic printing, such as book and magazine covers or postcards.

This property is very subjective and individual to each buyer and end use as skin colour and food are better reproduced on ‘warm’ (yellow) whites and not blue whites. Grammage: The grammage of the paperboard is assessed in accordance ISO 536. PH: Surface pH is measured on a water extract and is on a scale of 0-14, 0 being acidic, 7 neutral and 14 alkaline. Stiffness: Stiffness is one of the most important properties of paperboard as it affects the ability of cartons to run smoothly through the machine that erects, fills and closes them. 1879 saw the development of mechanical die cutting and creasing of blanks.

Paperboard is (like paper) a vegetable-fibre web formed from a water suspension. Virgin fibre pulp is naturally brown in colour, because of the presence of lignin.

The Paper & Paperboard market size (2007) had a value of 630.9 billion USD and a volume of 320.3 million metric tons . The paper and paperboard industry is quite energy and capital intensive. Folding carton first emerged around the 1860’s and was shipped flat to save space, ready to be set up by customers when they were required.

Economies of scale apply, because of which a few large players often dominate the market place. In 1911 the first kraft sulphate mill was built in Florida and in 1915 the gable top milk carton was patented and in 1935 the first dairy plant was observed using them.

wood) or from recycled waste paper. According to ISO standards, paperboard is a paper with a basis weight (grammage) above 224 g/m², but there are exceptions.

In cases where the same kind of pulp is being used in several layers, each separate layer is treated and shaped individually in order to create the highest possible quality. Stiffness also gives strength and reduces the propensity of a carton to bulge under the weight of settling flowable contents such as cereals.