Mark J. Kirwan Paper and Paperboard Packaging Technology
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CORRUGATED FIBREBOARD PACKAGING
367
Wash-boarding
Using low grammage papers in the outer liner creates in some cases, but not
consistently, a wash-boarding phenomena, as indicated in Figure 11.56.
In post-print, i.e. printing on corrugated board, it is difficult sometimes to
obtain good results, especially when it is required to print an illustration in solids
and halftone or a bar code.
It is much easier to achieve a high-quality print result by pre-printing white top
liners, i.e. by printing reel to reel prior to production of corrugated board.
All printing parameters (consistency, ink consumption for a chosen optical
density, etc.), in general, are easily achieved with pre-print technology.
Pre-print versus post-print
A comparison between 39 cm × 35 cm × 22 cm RSC boxes was made with pre-print
white top liner and post-print boxes using the same grades of paper liner.
The results obtained are shown in Table 11.15.
In this analysis, no significant difference was observed in BCT performance
between pre- and post-print. The customer, however, elected to use the pre-print
boxes due to the better print quality.
Corrugated board manufacturing and converting processes are being continu-
ously improved by, for example, the installation of infrared drying equipment to
improve the print quality of post-print corrugated board and thereby largely
reduce the difference between pre-print and post-print quality.
Figure 11.56 Wash-boarding effect of print on corrugated board surface with low grammage white
top double face.
Table 11.15 Pre-print compared with post-print
Pre-print No print Post-print
BCT in newtons 2470 2450 2320
Deviation in % 4 4 6
Difference in % 0 6
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
For the other thin boards (mini-fluted such as E, F, G and N), it will be interesting
to evaluate the difference between pre- and post-print.
11.3.5 Packaging for food contact
Foodstuff safety and quality are of paramount importance to consumers, manufac-
turers and regulators. Both can be influenced by the fitness for the purpose of the
packaging and its performance throughout the logistics chain.
Thirty-two percentage of the total European production of corrugated board is
used for food packaging, including transport packaging. If beverage packaging is
included, this rises to 40%.
A significant proportion of this production is used for direct contact with food
but most of the applications are for trays for fruits and vegetables. The volume
used for this purpose varies widely across western Europe, but in some areas it
may be as high as 20% of total production.
The proportion of corrugated packaging used for other direct food contact
applications are much smaller and estimated as follows:
•
1%, approximately, for fatty/aqueous foodstuffs (pizza, burgers, French-fries
as fast food, fresh meat, poultry and fish)
•
1%, approximately, for dry/frozen foodstuffs (bread, frozen meat, poultry
and fish).
Though a significant proportion of the total tonnage is not covered by the legislation
on direct food contact, some of this proportion may still be used in applications
where food safety is critical.
European Framework Directive 89/109/EEC – on the harmonization of laws of
the member states relating to materials and articles intended to come into contact
with foodstuffs – is the Framework Directive and has been transposed into the
legislation of each member state of the European Union.
The future Resolution for Paper & Board from the Council of Europe for paper
and board for food contact comprises a main section dealing with the general prin-
ciples and some specifications applying to both virgin and recovered paper. There
are three technical documents:
•
The Good Manufacturing Practice (GMP) – in order to produce paper for
food contact we must apply the GMP. This means implementing good
hygiene practices throughout the production process.
•
Inventory List – only materials which are on this list may be used in paper
and board manufacturing (chemicals, additives, etc.).
•
Guidelines on Recycled Fibre Usage will restrict the use of recovered paper
in the manufacture of paper for direct contact with fatty/aqueous foodstuffs.
This application will require the use of papers not normally used for
corrugated packaging.
CORRUGATED FIBREBOARD PACKAGING
369
For the packaging of fruits and vegetables in corrugated packaging, we can use all
grades of waste paper for manufacturing paper. However, this packaging does
have to meet the required specification on the content of pentachlorophenol (PCP).
The PCP level has to be below 150ppb.
For other dry and non-fatty product contact we can use all grades of waste
paper, but we have to comply with the stated maximum levels of PCP, phthalate,
polycyclic aromatic hydrocarbons (PAH) and benzophenone.
Until 2004, for direct food contact applications, such as pizza boxes, the
recycled papers currently in use in any of the layers of corrugated board are
not authorized. This means that for a product such as pizza and similar
products which are to be packed in direct contact with corrugated fibreboard,
only paper combinations made from virgin fibres may be used (see EU
Directives).
This is an evolving situation which should be checked by readers. At the time
of publication some 160 000 tons of corrugated fibreboard is currently estimated to
be in use in Europe for such applications. In Europe, test conditions and methods
of analysis for the specified contaminants and a practical guide are expected to be
published at EU Commission level.
11.4 Good manufacturing practice
The International Good Manufacturing Practice Standard for Corrugated and Solid
Board was published in October 2003 by the European Federation of Corrugated
Board Manufacturers (FEFCO) and the European Solid Board Organisation
(ESBO). This is concerned with the manufacturing of corrugated and solid board
in a controlled environment as far as quality, hygiene and traceability are concerned.
For details see Fefco website.
11.5 Corrugated fibreboard and recyclability
Wood and paper products are part of an integrated eco-cycle based on photo-
synthesis which involves the conversion of water, carbon dioxide, nutrients and
solar energy into renewable woody biomass.
Once consumed and collected separately, wood, discarded packaging and other
paper products can be recovered to start a new life as a secondary raw material or
bio-fuel.
Concerning resources, virgin and recycled fibre products are complementary.
They cannot exist separately. The optimum level of recycling depends on a
number of economic, social and environmental aspects, such as the geographical
location, the collection potential, the technical limitations to recycling, etc.
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
In addition, the long-term use of wood-based products represents an expanding
reservoir of carbon removed from the atmosphere. On an average one tonne of
paper contains some 1.33 tonnes of carbon equivalent CO
2
.
Recycling is an economic and technical reality for the wood and paper industry
which has, as a consequence, become one of the highest industrial recyclers. In
the paper industry, recycling rates – measured by the use of recovered fibres as
a percentage of domestic consumption – are high, ranging from 35 to 55% in the
regions covered.
For packaging papers (corrugated and cartons), the level of recovery can reach
70%, but it is different in each European country, as shown in Figure 11.57.
To improve the environmental performance of packaging products, the Euro-
pean Directive 94/62 allows manufacturers and users to reduce the weight of the
packaging but not the weight of the individual papers. However, the vision that
for corrugated fibreboard, the two are tied together, i.e. weight of papers= weight
of case, is not completely correct. This is because the possibility exists for
changing the construction, i.e. replacing BE flute with C flute or applying an
alternative professional solution.
Lightweighting is encouraged as it leads to a reduction in the use of resources
but with respect to the strength of paper, one has to take into account the fact that
repeated recycling leads to lower strength, as indicated in Figure 11.58.
The paper industry fulfills the maximum targets of recovered and recycled rates
required in the current EU targets. There are also restrictions in the allowable
heavy metal content which has to be below 100 ppm.
Figure 11.57 Waste management in the Western Europe: paper recovery level. Source: Based on the
CEPI (European Confederation of Paper Industries) data for 2002.
80%
70%
60%
50%
40%
30%
20%
20%
0%
Germany
Austria
Ireland
Italy
Belgium
Portugal
UK
Spain
France
Total EU
Netherlands
Sweden
CORRUGATED FIBREBOARD PACKAGING
371
In summary, it must be emphasized that paper packaging, such as corrugated
fibreboard:
•
is based on a naturally renewable resource
•
is easily recycled
•
material which is not suitable for recycling is energy recoverable.
References
Aspler, J.S., S. Davis, S. Ferguson, N. Gurnagul & M.B. Lyne, Reproductibility of the IGT surface
strength test, TAPPI Journal, vol. 68, no. 5, pp. 112–115 (1985).
Azens, J.J., Extent of crushing, USFO Documents techniques, no. 42 (1982), no. 43 (1983) and
no. 44 (1985).
Differential Micrometer, USFO French patent, Contact Ondef France (new name of USFO).
European Framework Directive on Material for Food Contact 89/109/EEC.
Gunderson, D.E., A method for compressive creep testing of paperboard, TAPPI Journal, vol. 64,
no. 11, pp. 67–71 (1981).
McKee, R.C., J.W. Gander & J.R. Wachuta, Compression strength formula for corrugated boxes,
Paperboard Packaging, vol. 48, no. 8, pp. 149–159 (1963).
Nordman, L., E. Kolhonen & M. Toroi, Extent of crushing, FEFCO Congress (1978).
Pijselman, J. & J. Poustis, Researchers develop boxboard strength tests, Paperboard Packaging, no. 2,
pp. 66B–68B; no. 3, pp. 110B–110D (1982).
Pommier, J.C. & J. Poustis, Caisse en carton ondulé: Performances réelles, Revue ATIP, vol. 40, no. 7,
pp. 397–400 (1986a).
Pommier, J.C. & J. Poustis, Formation de feuille pour une utilisation optimisée du papier, La Papeterie,
no. 103, pp. 45–50 (1986b).
Pommier, J.C. & J. Poustis, Multiply packaging papers for better printability and runnability, Pira
Paper and Board Division Conference: New technologies in multiply and multilayer structures,
Session 111, no. 10, Bristol (May 1987).
Figure 11.58 Impact of recycling on paper quality (burst index versus number of cycles).
6.0
5.0
4.0
3.0
2.0
024
Number of recycles
Burst index
6810
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
Pommier, J.C. & J. Poustis, New approach for predicting box stacking strength, Revue ATIP, vol. 43,
no. 5, pp. 217–221 (1989).
Pommier, J.C & J. Poustis, Bending stiffness of corrugated board prediction using the finite elements
method, Mechanics of Wood and Paper Materials, ASME AMD, vol. 112/MD – vol. 23, edited
by R.W. Perkins, pp. 67–70 (1990).
Pommier, J.C., J. Poustis & J.J. Azens, TAPPI Corrugated Containers Conference (1988).
Pommier, J.C., J. Poustis & F. Lalanne, Testing the printability of board for flexography, Paper
Technology – VIII, pp. 22–24 (August 1989).
Poustis, J. & F. Vidal, Proceedings on Moisture-Induced Creep Behavior of Paper and Board,
December 5–7, STFI Stockholm, pp. 181–193 (1994).
Repya, J., Jr – Flexo preprint shows potential for continued phenomenal growth, Flexo, pp. 30–42
(October 1987).
Springer, A.M., J.P. Dullforce & T.H. Wegner, TAPPI Journal, vol. 68, no. 4, pp. 78–82 (1985).
Thielert, R., Determination of stacking load life relationship of corrugated cardboard containers,
TAPPI Journal, vol. 67, no. 11, pp. 110–113 (1984).
Thielert, R., Edgewise compression resistance and static load – lifetime relationship of corrugated
board samples, TAPPI Journal, vol. 69, no. 1, pp. 77–81 (1986).
Websites
www.smurfit-group.com.
www.fefco/ESBO.org (site includes International Case Code).
12 Solid fibreboard packaging
Mark J. Kirwan
12.1 Overview
Solid fibreboard is primarily used for distribution packaging. It is a rigid,
puncture-resistant and water-resistant material, which varies in thickness from
0.8 to 4.0 or 4.5 mm and in grammage from around 550 to around 3000 g/m
2
.
Solid board is either made on a multi-ply paperboard machine forming with
vats, Fourdrinier wires, or is made by a combination of forming methods. It is
also made by multi-ply lamination. The higher thicknesses are always made by
laminating two or more layers of paper or paperboard together to provide the
strength necessary for the intended use. Additional materials, including poly-
ethylene (PE), may be incorporated to meet specific performance needs. The board
is cut into sheets, printed and converted into boxes, trays and other paperboard
structures.
Solid fibreboard is used in a wide range of packaging and display applications,
such as:
•
packaging of meat, poultry, fish and horticultural produce in boxes and trays
•
promotional displays in self-service merchandising
•
games and games packaging
•
slip sheets in bulk distribution and storage
•
cell divisions for glass and plastic bottles in corrugated cases
•
packaging of engineering products
•
export packaging.
In Europe, the largest market for solid board packaging is for poultry, which
together with meat account for around 60% of the usage. Table 12.1 indicates the
percentage of overall European market usage. However, the actual percentages
of the usage of solid board in specific countries for each market will reflect the
Table 12.1 Percentages for typical European
market usage of solid board production
Source: Kappa Packaging.
Markets %
Horticulture 15
Meat 25
Poultry 35
Fish 10
Others 15
Paper and Paperboard Packaging Technology
Edited by Mark J. Kirwan
Copyright © 2005 by Blackwell Publishing Ltd
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
relative importance of the various markets in each country. Hence the proportion
used, for example, in horticulture may be significantly higher than 15% in some
countries and lower in others.
Standard quality solid fibreboard is more resistant to water and damp conditions
than standard corrugated fibreboard. The water resistance of solid fibreboard can
be significantly improved during manufacture to meet the needs of differing wet
environments. Performance needs can be met for packing and storage in frozen,
chilled, ice-packed, wet or humid conditions. Higher levels of moisture resistance
are achieved by internal treatment (sizing) of the board during board manufacture
and by the use of kraft facing, or liner, extrusion coated with PE on one or
both sides.
Inevitably, solid fibreboard packaging is compared with corrugated fibreboard
packaging. At equal grammage, a case made from corrugated fibreboard will have
a higher box compression strength as a result of its higher thickness.
At equal box compression strength, the solid fibreboard box will be heavier and
as the weight of the material has a major influence on the cost, the corrugated
fibreboard container is preferred.
The solid fibreboard container will, however, be specified where its strength,
toughness, puncture and water resistance are essential for a satisfactory packaging
performance in specific conditions of use, which can include rough manual
handling in cold and wet environments.
Though both solid and corrugated fibreboard containers are normally thought
of as one-trip packages, where it is feasible to specify multi-trip usage then
solid fibreboard is a better choice. This is because, it is less easily crushed than
corrugated and where it is damaged, it is easier to repair with self-adhesive tape.
Solid fibreboard packaging is manufactured primarily from recycled material.
It is both recyclable and biodegradable at the end of its useful life. It can be either
collected from households and businesses, or from ‘bring’ systems, to be returned
to a mill which uses recovered paper and paperboard to be recycled in the
manufacture of solid fibreboards.
12.2 Pack design
A wide range of packaging designs has been published in the International
Fibreboard Case Code (www.fefco/ESBO.org). The European Solid Board
Organisation (ESBO) has collaborated with the European Federation of Corrugated
Board Manufacturers (FEFCO) in the preparation of the Code. It is a structured
presentation of existing box designs with a code number assigned to each design.
The Code is used worldwide and has been adopted by the United Nations. It has
also been adopted by the International Corrugated Case Association (ICCA).
In addition to the designs in the Code, individual solid fibreboard packaging
manufacturers can extend the design range with customised packaging solutions to
meet specific market needs.
SOLID FIBREBOARD PACKAGING
375
Solid fibreboard packaging is supplied flat to save space in storage and
distribution. It can be erected by the packer manually or with mechanical
assistance. Where product volume is high, and a high packing speed is required,
fully automatic machinery is used for erecting, packing and closing. The solution
in any given application depends on the volume of usage and the packaging
environment.
Typical packaging designs are as follows:
•
separate base and full depth lid both based on a 4-point glued blank
(Fig. 12.1)
•
integral full depth hinged lid and tray based on a 6-point glued blank (Fig. 12.2)
•
double end wall self-locking tray (Fig. 12.3)
•
tray with ledge at each end with stacking and holding features, based on
8-point glued blank (Fig. 12.4)
•
stackable tray with clipped-in plastic corner supports (Fig. 12.5).
12.3 Applications
12.3.1 Horticultural produce
Fruit, vegetables and flowers are packed by the grower, or in co-operatives,
for supply to the markets on a daily basis. Natural produce is best packed in
Figure 12.1 Separate base and full depth lid, both based on a 4-point glued blank. (Reproduced, with
permission, from Alexir Packaging Ltd.)
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water-resistant solid fibreboard to keep the product fresh during storage and
transportation.
Flowers are frequently packed in lidded trays, i.e. cartons comprising a base
and a lid. Fruit and vegetables are packed in machine-erected trays that include
stackable features, which enable packs to be stacked 10 high on a pallet. Some
products may be packed wet.
Figure 12.2 Integral full depth hinged lid and tray based on a 6-point glued blank. (Reproduced, with
permission, from Alexir Packaging Ltd.)
Figure 12.3 Double end wall self-locking tray. (Reproduced, with permission, from John Wiley &
Sons, Inc.)