The philosophy of choice
The paperboard choice is determined by the end use application. We recommend, as the first priority, that the end use needs are analysed in terms of appearance and performance.
Aspects of appearance and performance needs for the two major applications, graphical and packaging products, are described below.
Graphical applications can be postcards, brochures, or book covers. The purpose is to convey a message and paperboard is the medium. The medium is always a part of the message, so the appearance of the medium must correspond to the message it carries.
Printed texts and graphic images are used to convey the message. A metallic, glossy or matt appearance is an effective way of giving the graphical product, such as a magazine cover, an exclusive image. Relief and creative shapes can be used to generate interest.
A graphical product that may be handled many times, for example a book cover, requires considerable durability.
Transportation costs can be a major part of the total production cost in graphical applications, for example postage costs when mailing brochures to customers.
The primary task of a package is to protect the contents from the surrounding environment, which might include impacts during handling, pressure in stacking, and extremes of temperature and moisture. In addition to its strength the paperboard package is also very suitable for promotional purposes.
During transportation the protection requirement is decisive, but on a shelf in the grocery store the package
is more promotional than protective. The major purposes of the package, which can change in emphasis during the products life cycle, are:
• Protect the product during transportation and storage.
• Promote the product with an attractive appearance.
• Inform the consumer about how to use the product.
• Protect the product during consumer use.
The demands for protection might vary as well as the needs for promotion. Each end use application has its own combination of protection and promotional requirements.
The package promotes the product and creates an image of the product for the customer. The product and the package must create the same impression. An exclusive perfume needs a package with a corresponding appearance, for example a metallic finish. Pharmaceutical products often have packages which are very white to emphasise the image of a clean and efficacious product.
Packages with creative shapes attract attention. An existing product might be given a new package to increase sales. Paperboard as a material provides endless options for constructing creative shapes.
Physical protection needs
The concept of physical protection involves the end user’s requirement that the packages withstand external forces in order to protect and hold its contents under various conditions. This protection is needed during transport and storage.
To meet extreme requirements, e.g. deep-freeze applications, additional functional protection is required.
Protection can also be vital during use. A cigarette pack, for example, must still look attractive after being carried in a handbag or pocket.
Possibilities and contradictions
Promotional and physical protection needs are met by the properties of the paperboard, e.g. smoothness, stiffness and strength. Whilst it is always possible to find an optimum paperboard solution for packaging and graphical needs it is important to realise that properties such as smoothness, stiffness and strength, while they all vary with density, do so in different ways due to the laws of nature.
Limitations due to the laws of nature
Stiffness and strength are two properties which are dependent on the density of the paperboard, but in opposite ways. This contradiction is due to the laws of nature and is related to the characteristics of the cellulose fibres. The general relationship between stiffness, strength, surface appearance and density is shown in the illustrations.
Relative economy of production
If a product is expensive, the package will be more intricate and exclusive to match the product. However, the cost of the package as a percentage of the value of the product is still very low.
Runnability is a property which is of great importance when comparing the economy of production of various materials. If the chosen paperboard causes a lot of production stops in converting and filling, due to low runnability, it will result in a costly package. A wise choice in the beginning saves a lot of money in the end.
When considering production economy in choosing paperboard it is important to have an overall view.
The importance of consistency cannot be overemphasised. The demand for consistency applies to all paperboard properties, including both appearance and performance parameters.
Two aspects of consistency are relevant:
• consistency within the order
• consistency between orders.
The cost benefit of conversion and use without problems and wastage is significant. Short runs with frequent make-ready stops for new jobs put increased demands on reliability. It is a great advantage if settings from a previous run can be used again and again, thereby avoiding costly adjustments.
When choosing a paperboard it is therefore important to choose a paperboard supplier that has a documented reliability. The consistency criterion is probably the most important paperboard requirement.
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