Fibre-based Packaging ::
[Previous :: Introduction]
Overview
Fibre-based packaging can be described simply as packaging made from the fibres of natural and sustainable raw materials. Fibre-based packaging is an essential element of all supply chains with the average consumer interacting with 10 to 20 pieces of packaging each day.
Figure 1 :: Supply Chain
A large number of these packages are built mainly from paper and board or contain paper and board parts, e.g. cardboard boxes. The fibres in paper and board provide the packages with strength and structure. Coatings and additives, e.g. starch, can be combined with the fibres to enable high quality printing, grease resistance and other useful properties.
The pulp and paper industry is at the forefront of environmentally friendly packaging, with the distinct advantage that its basic raw materials are not only renewable, but also recyclable and degradable (i.e. they brake down naturally over time).
Figure 2 :: Packaging Recycling as a Percentage of Total Material Recycling
[Source: www.wasteonline.org.uk]
Packaging demands are constantly shifting to meet the requirements laid down by functionality issues (the shape of the products etc.) economic improvements (anything from better fork lift trucks to bigger shelves at the supermarket) and the introduction of new environmental legislation. In this changing market place, the potential of fibre-based packaging is enormous.
What is it made from?
Fibre-based packaging is made almost exclusively from pulp produced from the raw material, trees and plants. As with all industries, economic factors (money) play a large part in determining the species of trees and plants used. At the international level by far the largest amount of fibre used for papermaking comes from wood pulp, approximately 90 percent of global pulp production. Various other sources of pulp account for the remaining 10 percent.
A breakdown of fibres used for packaging can roughly be classified as follows:
- Wood fibres: coniferous (softwoods) and deciduous (hardwoods)
- Bast fibre:: flax, hemp, jucie and ramie
- Other stems ('grasses'): straw bamboo, bargasse and maize
- Leaf fibres: esparto, manilla and sisal
- Seed hairs: cotton
- Synthetic fibres and pulps
Figure 3 :: Photograph of pulp
The Manufacturing process
Pulp is the generic term for a wide range of products resulting from the manufacturing processes that involve the chemical and/or mechanical treatment of various types of plant material.
Wood pulp, like other types of pulp, is manufactured by separating the wood fibres which are held together by a material called lignin. The fibres can be separated by either mechanically tearing them apart or by chemically dissolving them. Over the years, research and development programmes have given rise to new systems that combine aspects of both processes, blurring the boundary between the two families of pulp.
Figure 4 :: Machines used in pulp manufacturing
[Source: www.paperloop.com]
Mechanical pulps (high yield pulps)
These are characterised by the fact that a very high yield is produced, in the region of 85 to 95 percent. The yield simply means the amount of original wood retained in the final product. The most common use for mechanical pulps is newsprint and ground wood printing-writing papers.
Chemical pulps (low yield pulps)
One of the main objectives of chemical pulping is to remove as much as possible of the lignin and extractives. The result is a much lower yield, in the region of 40 to 55 percent. The pulps produced are substantially stronger, easier to whiten and less likely to lose their brightness over time when compared to their mechanical counterparts. One of the most common uses for chemical pulps is white writing paper.
Regardless of the process used, one of the most important determining factors on the properties of a particular pulp yield is the characteristic of the wood that starts the process, e.g. the species, age, density, moisture content and the time that has elapsed since it was cut.
Both mechanical and chemical pulps, although different, go through the same initial process.
Figure 5 :: Stages of Pulp Processing
- Stage 1 :: Defibration. This is where undesirable fibrous and non-fibrous materials are removed, e.g. knots in wood pulp.
- Stage 2 :: The screening process. The remaining pulp is then screened for a dual purpose. One is to totally separate the fibres and the other is to remove any unwanted material from the fibres.
- Stage 3 :: Cleaning. This is where any small particles of dirt and grit that remain in the fibres are removed. This stage also marks the end of the mechanical pulp process.
- Stage 4 :: Unbleached pulp. At this stage, much of the unbleached pulp can be used for products that do not attach importance to colour, eg boxes, bags and newsprint. For higher grades (quality) of paper, such as writing paper, treatment is necessary in order to whiten the pulp. This treatment is known as bleaching. Bleaching involves heating or cooking the pulp as well as oxygen being blown over it in order to whiten the dark colour of the pulp (shown in the diagram below).
- Stage 5 :: Finishing. At the next stage, if the pulp is to be transported either for direct retail or to a paper or board mill, it will need to be drained of any remaining moisture. If the pulp mill has an integrated paper mill, the draining process is not required.
Figure 6 :: Pulp Bleaching
The dark colour of the pulp is mainly due to residual lignin.
This is removed gradually during bleaching.
[Source: www.chmitech.com]
Where does it all come from—which countries produce pulp?
This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.
| Europe (main two) | Europe(the rest) |
|---|---|
| Sweden and Finland | Norway, Portugal, Spain, France, Germany, Belgium, Luxembourg, Denmark, Greece, Great Britain, Ireland, Italy, Netherlands, Austria, Switzerland, Czech Republic, Poland, Turkey, former USSR |
Recycled fibre—the future of pulp?
[See also the page on Recycling and Waste Paper]
With one eye keenly trained on the environmental impact of producing pulp for fibre-based packaging, recycled and recovered fibre is an increasingly utilised resource. This is not only a readily available raw material, there is also the added advantage of reducing the solid waste found in landfill sites.
Recovered paper can either be repulped alone, or blended with virgin pulp to be reused in a wide variety of paper products. Examples include; packaging materials, printing papers, sanitary papers and newsprint.
Figure 8 :: Recycled sanitary tissues, newsprint and printing paper
Sources for recycled fibre are unsurprising, but nevertheless worthy of note. Most are sourced from commercial enterprises such as shops and manufacturing plants. The next largest providers are offices, followed by newspapers.
As recycled paper originated as waste paper it goes through a process of 'cleaning' to remove any possible contaminants such as metal, plastic etc.
Associated problems with using waste paper
- Recycled paper can and often does contain foreign substances that must be removed at an additional cost.
- Waste paper is of varying quality.
- The quality of the finished paper made with waste paper can be inferior to virgin paper.
- The water systems used during the paper making process become more polluted if waste paper is used, increasing treatment requirements and therefore increasing cost.
- Maintaining cleanliness of the mill itself is made more difficult with waste paper stocks on the premises.
Figure 9 :: Pulp waste and an image encouraging recycling to protect the earth's natural resources
Trade bodies regarding pulp production in Europe
There are trade bodies for most countries in Europe that produce pulp. The banner European organisation is known as the Confederation of European Paper Industry (CEPI). This gives useful information as well as links to other individual European country trade bodies such as the Paper Federation in the United Kingdom.
CEPI web site :: www.paperonline.org
Paper Federation of Great Britain - PFGB
An example of the sort of information available from the trade bodies with regard to regulations is;mills that make pulp designed for food contact uses, including both packaging and non-packaging, should comply with the Paper Federation's good manufacturing practice code. To protect the consumer, any product made from pulp must comply with certain standards so no illness is caused. For example, the cardboard container for a chicken kiev must not have any chemicals in it that could harm the food and in turn harm the consumer when they eat the chicken kiev.
For more information regarding the UK visit the Paper Federation address below.
PFGB web site :: www.paper.org.uk
Other examples
- France COPACEL
- Confederation of the French Pulp, Paper and Board and Industry
- Finland FFIF
- Finnish Forest Industries Federation
- Sweden SFIF
- Swedish Forest Industries Federation
[Next :: Paper and Board Manufacturing]
