Mark J. Kirwan Paper and Paperboard Packaging Technology

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RAW MATERIALS, PROCESSING AND PROPERTIES

Some paper and paperboards are extrusion coated with plastics such as PE on

one or two sides. Packs incorporating such materials may be sealed by heat sealing

either by sealing plastic to paper, as an overlap seal, or plastic to plastic. The plastic

is softened and becomes tacky/molten under heat and pressure and then cools and

resolidifies forming a strong seal. A strong heat seal also requires good fibre tear

in the paper or paperboard material.

Heat-sealable tea-bag tissue incorporates a heat-sealing medium such as PP in

the form of a fibre dispersed within the very thin sheet. With multilayer thicker

materials, such as paperboard, the fibre tear must rupture the internal layers when

the seal is peeled open.

1.5.3.17 Taint and odour neutrality

Some products are sensitive to changes in their taste, flavour or aroma. Examples

are fat-containing food products, such as butter, vegetable fats and chocolate.

Other flavour and aroma sensitive products are tea and coffee and a range of

tobacco products. Changes can occur by loss of flavour through the packaging, the

ingress of unwanted flavours from the external environment and by the transfer of

flavours originating in the packaging. The first two potential causes are prevented

by augmenting the paper and paperboard with additional barrier materials, such

as aluminium foil, a metallised coating on plastic film, PVdC coated oriented

polypropylene film, etc. Whilst all packaging associated with flavour and aroma

sensitive products has to meet critical requirements, here we are concerned with

aspects which potentially can apply to paper and paperboard packaging.

The best approach is to ensure that when odour and taint critical packaging

is required, the raw materials are chosen carefully. The range of paper and

paperboard materials is wide and depending on the needs of the product, many

papers and paperboards can be ruled out initially from what is known, doubtful or

potentially variable about their constituents.

For the most critical products virgin fibre is necessary. The best results are

achieved with chemically separated and bleached virgin pulp. For some critical

products paperboard with a mixture of this material and mechanically separated

virgin pulp has also been approved and is used widely. The concern with these

materials is not the pure cellulose fibre, which is inert and odourless, but other

residual wood originating compounds which may not be fully removed by

bleaching and which are either not removed, or only partially removed, in the case

of mechanical pulp. The pulp can contain residual fatty acids from the wood and

these compounds are oxidised over time producing odiferous aldehydes.

Another potential source of odour and taint can be residual compounds origin-

ating from the chemicals which are used for the mineral coating – not so much the

mineral compounds themselves but the synthetic binders (adhesives) which bind

the particles together and to the base sheet of fibre.

Paper and paperboard-based packaging for use with products which have

critical odour and taint-free requirements can be checked by panels of selected

people using sensory methods based on smelling and tasting. Where odour or taint

PAPER AND PAPERBOARD PACKAGING TECHNOLOGY

is detected, the compounds responsible can be identified by gas chromatography

and mass spectrometry. The concentration of compounds can be measured by gas

chromatography, see Section 10.8. Many other potential sources for odour and

taint arise as the result of printing, varnishing and other conversion processes.

1.5.3.18 Product safety

The basic requirement of packaging is that it should ensure the quality of the

packed product however that is defined. In some cases, this leads to the need for

assurances regarding the safety of food in direct contact, or close proximity, to

specific packaging materials. It also leads to a similar need with respect to the

packaging used for toys.

These needs are defined in regulations. In the United States, the regulations are

given in the ‘Code of Federal Regulations, Food and Drugs Administration

(FDA)’. In Europe, the most widely quoted are those formulated by the ‘Bundesge-

sundheitsamt (BGA)’ and in Holland there are the ‘Warenwet’ regulations. For toy

packaging, the regulations are embodied in EN71 Part 3 (migration of certain

elements).

Users of packaging can show diligence in ensuring that regulations are met by

requiring evidence from suppliers, which approved laboratories have checked that

the materials concerned meet the appropriate regulations.

1.6 Specifications and quality standards

Having examined the appearance and performance properties of paper and

paperboard packaging materials, it is clear that considerable efforts have been

made to relate them to packaging needs. Test procedures which measure these

properties and relate them to market needs have been developed and used in

specifications.

Specifications are needed for a variety of reasons – communication of exact needs,

quality assessment, resolving disputes, compatibility of competing quotations and

as a basis for improvement.

The paper and paperboard market is international with pulp, paper and packaging

traded on a worldwide basis. Hence there has been a need for harmonisation of

test methodology. Test methods are developed locally and between suppliers

and customers on a one-to-one basis. These may become national standards

such as British Standards (BS), German Standards, DIN and TAPPI in North

America. In recent years, International Standards have been developed through

the ISO.

Tolerances which are realistic are an important requirement of specifications.

Over time, the needs and expectations of customers increase – equally the abilities

and achievements of suppliers have to respond to market needs. On-line computer

control has, in many cases, augmented laboratory testing, which of its nature is

historical. This development which is progressive and ongoing results in less

RAW MATERIALS, PROCESSING AND PROPERTIES

variability within makings and between makings, and less variability leads to

higher productivity.

Equally important is the requirement that quality management systems overall

must be seen to be effective. Many manufacturers now have their quality systems

independently and regularly assessed under the ISO 9000 series of Quality Standards.

Supplier audits are also undertaken.

1.7 Conversion factors for substance (basis weight) and thickness

measurements

It will already have been noted, e.g. in sections 1.5.3.2 and 1.5.3.3 respectively,

that different conventions are used in different parts of the world for the measure-

ment of basis weight and thickness.

It is, however, possible to convert from measurements in one convention to

another as follows:

Substance (basis weight) measured in lb/1000 sq.ft = 4.882g/m

, (grammage)

Substance (basis weight) measured in lb/3000 sq.ft = 1.627g/m

, (grammage)

Thickness measured in ‘thou’, (thousandths of an inch) = 25.4 micron,

(thousandths of a mm)

A thousandth of an inch is also known as a ‘point’ and, in the case of plastic

film thicknesses, as a ‘mil’. The SI symbol for a micron, or micrometre is ‘µm’.

References

Davis, A., 1967, Packages and Print – The Development of Container and Label Design, Faber &

Faber, London.

Grant, J., Young, J.H. & Waston, B.G. (eds), 1978, Paper and Board Manufacture, Technical Division

British Paper and Board Industry Federation, London, pp. 166–183.

Hills, R.L., 1988, Papermaking in Britain 1888–1988, The Athlone Press, London and Atlanta

Highlands NJ, p. 49.

Opie, R., 2002, The Art of the Label, Eagle Publications, Royston, England, p. 8.

PPI, 2002, Pulp and Paper International Facts & Price Book 2002. James, R., Jewitt, M., Matussek, H.,

Moohan, M. & Potter, J. (eds), Paperloop Publications, Brussels, pp. 47, 166.

2 Environmental and waste management issues

Mark J. Kirwan

2.1 Introduction

Anything environmental commands attention. We now know more about the

effects of human activity on the environment at local, regional and global level.

Society is concerned, as never before, about environmental issues. Since the

1960s, through education and the media generally, the general public has become

aware of the issues. We have seen the rise of the ‘green’ movement in the form of

non-governmental organisations (NGOs). The overall result has led to government

involvement at local, national and international level. There are regulations which

require the measuring and regular monitoring of critical factors which can affect

the environment.

There is a concern about the quality of life today, and in both the medium and

the long term. These concerns have been summarised as follows (Tickell, 1996):

•

population growth causing pressure on resources

•

deterioration of land quality

•

pollution of rivers, lakes and seas

•

limited freshwater availability

•

changes in the chemistry of the atmosphere – acidification, ozone depletion

and climate change attributed to the ‘greenhouse effect’

•

losses of species or reduction in biodiversity.

The key components relating to world population are life expectancy, which is

increasing, and birth rate, which is declining. The birth rate per 1000 is declining

but because of the numbers of people overall, the population as a whole increases.

Nevertheless, the figures for 2050 have been revised downwards in recent years as

the overall rate of population growth reduces (Table 2.1). The fact, however,

remains that more people will use more resources.

In addition to global and regional issues, there can be local environmental

issues which affect communities, such as the siting of a waste incinerator or a

wind ‘farm’, which are examples of the NIMBY (‘not in my backyard’) approach.

There is also concern about the effects of our activities on indigenous people and

forest-based communities.

Industry is a primary user of resources and creates additional environmental

impact through its manufacturing processes and the products it produces. The

effect of heightened environmental concern has caused industry to balance the

need to be technically efficient and profitable against the environmental needs of

society which are driven by people’s perceptions, resulting in a legal framework

within which industry must operate.

Paper and Paperboard Packaging Technology

Edited by Mark J. Kirwan

ENVIRONMENTAL AND WASTE MANAGEMENT ISSUES

Paper and paperboard packaging is subject to two aspects of environmental

concern. First, as an important part of the paper industry, it is subject to concerns which

apply to the paper industry as a whole. Secondly, it is subject to the concerns which apply

to all packaging.

In summary, these concerns comprise:

•

pressure on resources due to the increasing demand for paper and paperboard

•

wood, the main raw material, is sourced from forestry

•

environmental impact caused by the use of energy and freshwater

•

pollution in manufacture, particularly in fibre separation (pulping) and bleaching

•

packaging is perceived as wasteful in itself and, when discarded, after its

protective function has been completed, as a waste management problem.

The increasing demand for paper-based products arises from the increase in

population worldwide together with increases in per capita consumption associated

with rising standards of living. The disparities in consumption shown in Table 1.3

highlight the potential for increases in per capita consumption of paper-based

products.

Whilst there are environmental issues concerning forests, energy, water, impact

of industrial activity and waste management that are specific to paper and paper-

based packaging, such matters have also to be viewed in the context of agendas

driven by world realities. The issues of climate change (global warming), depend-

ence on fossil fuels (the ‘oil economy’), competition for scarce resources such

as freshwater, and what to do about ‘waste’, all set agendas with environmental

implications for society.

We are aware of the limitations of the planet Earth. We recognise ‘the global

village’ where actions in one location or sphere of activity can have regional and

worldwide implications. We used to see environmental issues in terms of a range

Table 2.1 World population 1950–2050 (median projection)

Source: Population Division of the Department of Economic

and Social Affairs of the United Nations Secretariat (UN, 2003).

Year Population (billion)

1950 2.5

1960 3.0

1970 3.7

1980 4.4

1990 5.3

2000 6.1

2010 6.8

2020 7.5

2030 8.1

2040 8.6

2050 8.9

PAPER AND PAPERBOARD PACKAGING TECHNOLOGY

of single issues, such as the concentration of a waste emission which when reduced

was seen as a problem solved. Now we appreciate that we must consider whole

systems where any change may have wider implications. Hence, there is a need for

holistic solutions.

We are asked if specific products, processes or practices are ‘environmentally

friendly’. These are difficult questions because everything we do, cause to be done

or merely observe has an environmental effect, and assessing the extent of that

effect involves a value judgement. Widespread and indiscriminate use of the

precautionary principle is not an option.

The guiding principle for society, when evaluating our approach to meeting the

demands of today and in the future, is to ensure that we operate in an environmentally

‘sustainable’ way.

2.2 Sustainable development

In 1987, the World Commission on Environment and Development, also known

as ‘The Bruntland Commission’, issued a report entitled ‘Our Common Future’.

This discussed, internationally, the concept and the need for sustainable

development. The report defined this as ‘development which meets the needs

of the present without compromising the ability of future generations to meet

their own needs’.

At Rio in 1992, the governments of various nations agreed that sustainability

had economic, environmental and social aspects which were equally important and

interdependent (United Nations Conference on Environment and Development).

This theme has been taken forward in a number of major areas including forestry

with significant coordinating leadership from FAO (United Nations Food and

Agricultural Organization):

Nations must manage their forests in a sustainable way so that present generations

can enjoy the benefits of the planet’s forest resources while preserving them to

meet the needs of future generations. (FAO, 2003)

Several leading paper companies are featured in the Dow Jones Sustainability

Indexes (DJSI) (www.sustainability-index.com). These indices are based on criteria

from companies which are evaluated in terms of quality of management and strategy,

together with performance, in dealing with opportunities and risks deriving from

economic, environmental and social developments. Such developments can be

quantified and used to identify and select leading companies for investment

purposes. In several annual reports, the DJSI has outperformed the market in

general, indicating that sustainability priorities enhance performance overall for the

companies concerned.

The position today, and for the future, is that paper and paperboard:

•

should not be a polluter in manufacturing, use and disposal

•

should not be a drain on irreplaceable resources.

ENVIRONMENTAL AND WASTE MANAGEMENT ISSUES

More, of course, can be said about both these points, but they are the bottom line – the

key messages irrespective of what may have applied in the past when our knowledge,

measurement techniques and understanding of environmental impact were much

less sophisticated than is the case today.

We should also be confident of the main benefit of paper and paperboard

packaging in that they protect far greater resources, in terms of the goods protected,

than are consumed in the manufacture and use of the packaging. This benefit is

achieved during the packing, storage, distribution, sale and consumption of food

and other manufactured goods.

Effective packaging, in which paper and paperboard-based packaging is a major

component, has revolutionised the safe distribution of all products, particularly food,

in the advanced industrial societies and to a lesser extent so far in the developing

world. It is acknowledged that packaging reduces waste.

Ample evidence exists of large-scale losses occurring during post-harvest and

distribution operations in developing countries. The subject was first addressed at the

World Food Conference in 1974. In 1977, the FAO carried out a study of post-harvest

crop losses in developing countries. This produced evidence of post-harvest waste.

Post-harvest losses were also presented at the 1996 World Food Summit. The results

have been summarised by Neil Robson (Robson, 1997), and the conclusion drawn

that ‘the world’s packaging professionals have a major task ahead if they are to

convince governments and opinion leaders of the vital role which packaging

should play in reducing food wastes’.

It is therefore important that paper and paperboard-based packaging continues

to be available and this has to be achieved in a sustainable manner. Sustainability

for paper-based packaging concerns the availability and use of the resources

needed to meet increasing demand and the minimisation of the environmental impact

of manufacturing, use and disposal. In summary, it concerns forestry, manufacture

of paper and paperboard, printing, conversion, packaging, distribution, consumer use

and the ultimate disposal of paper and paperboard-based packaging. These subjects

will now be discussed in terms of ‘sustainability’.

2.3 Forestry

Forests cover around 30% of the earth’s land area and are one of the essential

support systems which sustain life on Earth as we know it – the other essential

systems concern air, water, soil and energy.

Forests are important as they:

•

reverse the ‘greenhouse effect’

•

stabilise climate and water levels

•

promote biodiversity by providing a habitat for a wide range of animals,

birds, plants and insects

•

prevent soil erosion and protect watercourses

•

store solar energy.

PAPER AND PAPERBOARD PACKAGING TECHNOLOGY

The greenhouse effect occurs when radiant energy from the sun is unable to

escape from the earth’s atmosphere because of the build-up of gases, such as CO

These are believed to prevent the heat from escaping – acting, in effect, like glass

in a greenhouse – and so cause the temperature to rise. This is known as ‘global

warming’, which is considered to be a cause of climate change.

Carbon dioxide is the most common greenhouse gas. It is released when fossil

fuels like coal, oil and natural gas are burnt to produce energy in the form of heat

and electricity and when used in internal combustion engines. The world’s use of

fossil fuels releases about five billion tonnes of carbon into the atmosphere per

annum. The proportion of CO

in the atmosphere is increasing by about 5% a decade

and this is thought to be the main cause of global warming.

Trees grow by absorbing CO

and releasing oxygen. As trees grow, therefore,

they remove carbon from the atmosphere and so help to reverse the ‘greenhouse

effect’. This is known as ‘fixing’ carbon and the forest acts as a ‘carbon sink’ or

reservoir.

Growing trees process CO

from the atmosphere by photosynthesis (Fig. 2.1).

In this process, trees, in common with all green-leafed plants, using energy supplied

by the sun, convert CO

and water into simple sugars and oxygen. The sugars are

polymerised naturally and ultimately result in the formation of cellulose fibres.

Energy

Oxygen

Carbon dioxide

Figure 2.1 Trees grow by the combination of carbon dioxide and water, using energy from the sun.

This process, which emits oxygen, is known as photosynthesis. (Reproduced, with permission, from

Iggesund Paperboard.)

ENVIRONMENTAL AND WASTE MANAGEMENT ISSUES

A mature forest, however, also contains dead trees and other vegetation. As this

organic material decays, it actually gives off CO

. Also, growing trees emit oxygen

and decaying trees absorb oxygen. Hence, where the biomass (collective term for

trees and other vegetation) stays approximately constant in a mature forest, the

emission and absorption rates for oxygen and CO

remain in balance, and it is

incorrect to refer to such mature forests as being ‘the lungs of the world’. In

expanding forests, on the other hand, where there is an annual incremental net

addition of new wood volume, CO

is effectively removed from the atmosphere.

With respect to carbon ‘fixing’, area alone does not reflect the complete picture.

Location, climate, age of trees, soil, rainfall, competing species, proportion of

dead and decaying trees and other biomass, etc. are all important factors. Large

land masses and vegetation, or lack of it, including large areas of forest, are known

to be the major determinants of climate. Other factors are solar energy, temperature,

humidity, precipitation, condensation, atmospheric pressure and wind, which all

interact dynamically.

Forests prevent soil erosion and protect watercourses from silting – the destruction

of forests has resulted in humanitarian disasters through landslides and flooding.

Forests are important for the maintenance of the traditional form of life of forest-

based communities in the developing world. It is self-evident that forests provide a

habitat for many species, viz. animals, birds, trees, other types of plants and insects,

etc. It is also a fact that species evolve and some become extinct. Biodiversity has

entered the environmental debate with respect to the extent that human interfer-

ence in forestry is causing species to be lost by extinction. Some exceedingly high

losses have been predicted. However, the UN Global Biodiversity Assessment

(UNEP, 1995) states that ‘the rate at which species are likely to become extinct in

the near future is very uncertain’, taking note of ‘the discrepancy between field

knowledge and predictions’.

The importance of forests as a store of solar energy is less controversial, if not

fully appreciated. About 80% of the wood felled in the developing world is used as

fuel (Remrod, 1991).

In the industrialised countries, around 20% of the wood felled is used for fuel.

In the European Union (EU), about 1% of the energy used is derived from wood

though the proportion is likely to increase as the EU seeks to replace fossil-fuel

energy with energy from renewable sources, which include wood.

Forests, particularly in the industrialised countries, are also important in providing

an environment for leisure and for the commercial viability of small communities

working in forest-based activities.

Forests are therefore important for many reasons. FAO defines four types of

forest by ecological zone as follows:

•

Boreal (33% area) – these are forests in the northern parts of the Northern

Hemisphere, i.e. northern parts of Canada, Scandinavia and the Russian

Federation, including Siberia. The alternative name ‘taiga’ is used for the

boreal area of Russia. These forests are predominantly coniferous, i.e. with

PAPER AND PAPERBOARD PACKAGING TECHNOLOGY

pine, spruce, larch and fir, with a proportion of deciduous birch and poplar.

Some analyses refer to these forests as temperate coniferous.

•

Temperate (11% area) – these forests are mainly in North America and

Europe; they contain mixed coniferous and deciduous species.

•

Sub-tropical (9% area) – also referred to as warm temperate. An important

area for this type of forest is the south-east of the United States of America.

•

Tropical (47% area) – there are three types of tropical forest. The rain forest

is given the most publicity in areas such as the Amazon basin, Congo basin and

South-east Asia. However, the area loss in the arid dry forests and savannah

forests of South America, Africa and India are a greater cause for concern,

where the use of wood for fuel and unsuitable agricultural practices can lead

to desertification. The trees are predominantly deciduous (FAO, 2001, p. xxii).

Tropical and sub-tropical forests comprise 56% of the world’s forests, and temperate

and boreal forests account for 44%.

Figure 2.2 shows six categories of forest area which give a general indication of

where forests are located. FAO has defined the various types of forest area based

on tree size and concentration.

The main source for coordinating global statistics for forestry is FAO, and

reference should be made to its website for comprehensive details. They issue a

‘Forest Resources Assessment’ every 10 years. In the report of 2000, it is stated

that total forest area is 3.9 billion hectares, roughly 30% of the global land area.

(It is thought that between one half and two thirds of the land area was covered by

forest, thousands of years ago.)

Figure 2.2 Forest locations. (Reproduced, with permission, from the Swedish Forest Industries

Federation.)