Paperboard is a thin and flat material in sheet form made up from an interlaced network of cellulose fibres. It is usually made in several layers, combined together in the wet state. A white mineral pigmented coating is applied in one or more layers, on one or both surfaces, enhancing whiteness and smoothness and providing a surface for printing and varnishing. The main raw material for paperboard is cellulose, the basic organic matter of wood. The fibres are derived from different kinds of trees, mainly pine, spruce and birch. Also eucalyptus can be used. The process by which the fibres are separated from wood is known as pulping. Fibres derived directly from wood are known as "primary" or "virgin" fibres. When used paper and paperboard are repulped, the fibres are known as "secondary" or "recycled" fibres.
Paperboard can be divided into four different grades: SBB, SUB, FBB and WLC.
- SBB stands for Solid Bleached Board
- SUB for Solid Unbleached Board
- FBB for Folding Box Board
- WLC for White Lined Chipboard.
SBB, SUB and FBB are made from virgin fibres while WLC is mainly made from recycled fibres. Iggesund Paperboard produces SBB and FBB.
Virgin fibres have many advantages compared with recycled fibres. Virgin fibres retain much of their original strength. Paperboard made from virgin fibres is stronger and fulfils the best performance in printing, converting and use. The strength also makes it possible to maintain performance at to material weight. Also, virgin fibres are of known origin and, with carefully controlled processing, are free from any tendency to impart taint or off-odour so that purity requirements are fulfilled.
Not just paper
Paper is a commonly used material and medium for messages of our time. Paper has a long tradition as an accepted and well-established graphic material. It is no great step from paper to paperboard. Two types of paperboard can be identified: single-ply and multiply. In general terms, we can define single-ply paperboard as thick paper whereas multiply paperboard, as the name implies, consists of several layers. Multiply paperboard, sometimes called graphic paperboard, is available from Iggesund Paperboard in grammages from 180 g/m2 upwards.
A material offering many options
Man has an inborn desire to create, refine, develop and improve. Those urges make us look for base materials with properties suiting our aims; materials which can be designed to offer new associations or functions. When you need a strong, elastic material to create two or three dimensional shapes, combined with sophisticated illustrations, your obvious choice is graphic paperboard.
Traditionally, graphic paperboard is used for covers and envelopes of various kinds, since it is a stiff material giving stability to the printed matter; but graphic paperboard of the right type can offer much more. Its strength and elasticity make it an exciting and experimentally formable material in the hands of the designer. Creating geometrical, three dimensional products from paperboard is a real challenge, where the options are determined only by our imagination.
Graphic paperboard delivered by Iggesund Paperboard has properties making it very suitable for series production of complex geometrical shapes; for example, products having narrow radii, sharp corners and deep reliefs. Since the structure of paperboard differs from that of paper, special techniques have been developed to utilise paperboard. Unlike paper you should crease paperboard, before folding it, if you are to benefit from its advantages. Creasing is the technique developed to make distinct folding grooves. Properly made, a crease will prevent tension in the paperboard surface after folding.
For further information on paperboard conversion, refer to the Paperboard Reference Manual issued by Iggesund Paperboard.
Iggesund Paperboard is a leading supplier of graphic paperboard. Descriptions of these products and their data are contained in the Paperboard Product Catalogue. Basic and measurable properties of our graphic paperboard are:
- smoothness, whiteness and purity
- strength and elasticity
- uniform material quality
Together, these features offer the best possible image reproduction and printability, a strong and durable material, stability for three dimensional products, gluable, sealable and inter-lockable, distinct and resistant folding lines, adaptability for embossing and permanent relief figures, and also the options of lamination or coating with metallic or plastic materials.
Paperboard for packaging
Packaging is the external face of the product, thus becoming integrated with the product identity. A packaging material must provide a means for product promotion. One of the key elements of product promotion within an overall strategy is the appearance of the product package at the point of the sale. This is achieved through the graphical presentation and the creative and structural shape of the package. Design concepts can be "traditional", meaning similar to that of similar products or "innovative", meaning a departure from previously used designs. Design can suggest value such as "expensive", "exclusive", "value for money", "budget brand" etc.
Paperboard packaging powerfully conveys brand values. Its surface is ideally suited to accept print, varnish and a whole range of decorative finishes. Paperboard also has the ability to retain reproduced text and pictures on the surface in accordance with the specifier's expectations. The image of the product can be reflected accurately and correct product descriptions can be given.
The most sophisticated illustrations can be reproduced when using a virgin fibre paperboard with a suitable surface structure, good whiteness and surface smoothness.
- The contrast of the clean white paperboard surface to the print enhances the impression created by the illustration and text.
- The ability of the paperboard to withstand fading is vital for a lasting presentation.
- The clean, white surface can be embossed in order to create a relief image or pattern. This treatment gives the product an exclusive touch.
- Hot foil stamping and, all the more often, sophisticated printing methods are used to create metal-resembling surfaces. Hot foil stamping is the term used for the process where metallized polyester film is applied to the flat or embossed surface.
- A printable metallized plastic film in silver or gold can be laminated to the paperboard. This gives the finished product an impressive and luxurious image.
- The paperboard surface is durable, and the durability can be further enhanced by lacquering or plastic coating. Such coating gives efficient surface protection to abrasion.
Creative and structural shape
The creative and structural shape of the package offers additional promotional possibilities. With paperboard there is wide scope for designing shapes in two and three dimensions as a result of its properties of easy cutting, creasing, folding, gluing and sealing, together with the overall strength of the material. These properties facilitate the production of design options which it can be truly claimed are only limited by the imagination.
For the designer paperboard is an inspiring material with which to work. The demand may be for an unusual or expressive design, large main face panels for exposure in retail display or optimised volume for efficient distribution.
An important design need is that surface designs and prototype packs (samples) should be easily and cheaply available in order to compare alternative designs both visually and functionally and to facilitate test marketing. Paperboard pack prototypes can be made available today, both cheaply and quickly. CAD systems can produce small numbers of samples and larger numbers can be produced by a variety of techniques. Similarly, colour proofing is available through a number of techniques.
The packaging must protect the product against any physical damage to such an extent that the product's appearance and function will not be jeopardised. Packaging must also provide protection against any other unwanted biological or chemical changes that may occur under influence from, for example heat, cold, moisture changes, fat, light and oxygen.
Protection from mechanical stress
The package must protect the packed product, so that it is undamaged and fresh-looking when displayed in the store and in consumer use. It must be strong and durable, and endure mechanical handling as well as distribution and storage.
- Paperboard made from virgin fibres is a stiff, strong and tough material. An appropriate paperboard carton construction gives adequate protection in handling and storage.
- Cartons made from paperboard can be optimised in shape and volume to fit the demands and circumstances of the product and application.
Protection from deterioration damage
As a rule, paperboard by itself offers adequate protection for the packed product. Sometimes, however, ambient conditions require additional protection of the paperboard, in order to achieve an effective barrier. This is done by providing the paperboard with a surface coating of metal foil or plastic film. This coating can be on one or both sides, as determined by the requirements of the packaging. In this way the barrier functions are tailored to the application.
For certain products, such as chocolates and tobacco, it is important that no change in odour or flavour occurs. Paperboard made from virgin fibres is of known origin. It is processed in a carefully supervised process to be pure so that the consumer will not experience any effect from the packaging on the odour or flavour of the product.
Paperboard provides adequate protection against direct light. Board based on bleached virgin fibres has the best ability to resist influence by daylight or artificial illumination. The ageing effect is minimised, and hence this type of paperboard will marginally be subject to fading or becoming brittle in the course of time.
The stiffness, strength and toughness of paperboard gives the packaging good impression strength to protect and preserve the contents from physical damage. Paperboard preserves its good strength even under cold conditions or when frozen.
To some extent paperboard also resists absorption of moisture. However, the strength properties of paperboard are reduced as moisture ingress increases. This effect can be counteracted by internal sizing of the paperboard or by applying a surface coating of varnish, wax or plastic, depending on the degree of exposure to moisture.
Paperboard in itself is heat resistant to a certain extent, although the surface becomes discoloured as the temperature increases. As packaging for food to be heated in a convection oven or a microwave oven, the paperboard is usually provided with a heat resistant plastic PP (polypropylene), or PET (polyethylene terephthalate) coating. This provides the desired barrier properties during heating and preserves the fresh and appealing look of the packaging even after heating.
Fat resistance can be provided by applying a plastic coating of PE (polyethylene), PP or PET on the basic board. Where heat resistance, fat resistance and release properties are required the paperboard should be extrusion coated with PMP (polymethyl pentene). Moderate fat resistance can be achieved by the adhesive lamination of greaseproof and glassine papers to paperboard the greaseproof can be release treated where the product is sticky and tacky. Paperboard may also be laminated with aluminium foil which provides an excellent oxygen barrier.
Product safety requirements also involve the packaging and its protection performance. Product safety means product compliance with international food contact legislation and that the product should be safe for the consumer when used as intended.
- Paperboard made from virgin fibres is of known origin and manufactured under carefully controlled conditions. It is therefore consistent from making to making and safe for consumer use.
- Product safety rules and legislation for paperboard has been in existence for some time and are carefully observed in the paperboard industry. When required Iggesund Paperboard can provide a certificate to verify the suitability of the paperboard for the intended application.
Production and distribution
The production and use of packaging materials is based on well established, reliable and cost effective techniques and facilities.
- Paperboard has an ideal surface for printing. The printing industry covers a very wide range both in terms of the techniques used and the order sizes which can be undertaken.
- The packaging operation can meet a whole range of needs from those which are manual, to those which are mechanically assisted or fully automatic in forming, filling and closing at low, medium and high output, as required.
The primary distribution requirement is that the product meets customer needs reliably and cost effectively. Paperboard has several major advantages when one considers distribution. An important feature is that it is transported flat on pallets, or on reels, from the mill to the printer. Paperboard packaging is either folded flat or packed flat for delivery from the pack producer to the pack user, unlike glass, metal and some plastic containers. Paperboard packaging is also light in weight. It can be stacked, therefore making the best use of the expensive space on the supermarket shelf. These features not only have transportation implications, they also mean that less storage space is required.
Convenience in consumer use
Consumers take for granted that a package will serve its purpose as a container for distribution and storage. Packaging must be convenient for the consumer at all stages from the point of sale. It must be easy to store in a freezer, refrigerator, cupboard or drawer, or carried in a pocket or handbag. And, finally when its function is complete it should be safely and easily be disposed of. It can be crushed so that it does not take up much space prior to collection and resource recovery.
Paperboard packaging is light in weight, it is strong and resists crushing in storage and use. Depending on the product and package design, paperboard packaging can be tamper evident, easily opened and, where required, durable for repeated opening and reclosure. The contained product is easily recognised by the package shape and its graphical presentation - instructions for use can be printed clearly.
Sometimes it is important that the package is functional by offering added value in other respects. Examples of additional functions are carrying handles, tear strips or other opening devices, features for reclosure etc. The package can also have added value by fulfilling several functions, i.e. it can be more than just a container. A package that serves several functions can be more economical for the as it brings together several features in one product. In this respect the package make better use of raw material and is more energy efficient.
- The creative and functional abilities of paperboard offer opportunities for the designing of additional functions.
- If the paperboard is combined other materials even more functions can be integrated into one and the same package. An example where clever design and combined functions save energy and the environment is a package for ready-made food to be heated in an oven.
- The paperboard package offers added value by being suitable in a number of different situations. In distribution the carton serves as a package, in storage as a container, in cooking as a tray and serving dish and even possibly as a plate.