Mark J. Kirwan Paper and Paperboard Packaging Technology
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SOLID FIBREBOARD PACKAGING
377
Figure 12.4 Tray with ledge at each end with stacking and holding features, based on 8-point glued
blank. (Reproduced, with permission, from Papermarc Merton Packaging.)
Figure 12.5 Stackable tray with clipped-in plastic corner supports. (Reproduced, with permission,
from Papermarc Merton Packaging.)
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
12.3.2 Meat and poultry
These products are packed in trays with full-depth lids. Where PE lined solid
board is used, it must not be corona discharge treated as this would cause wet
products to stick to the PE. Such designs can be glued using hot-melt adhesives.
These packs can be used for a product weight range of 3–6 kg.
12.3.3 Fish
Fish may be packed wet, chilled or iced. The trays need to be in a leak-proof style, in
which the corner design is described as ‘webbed’. Two-side PE-coated solid board with
additional hard sizing provides the maximum protection for this type of packaging.
12.3.4 Beer (glass bottles and cans)
The wrap-around litho-printed multipack is the standard specification for this
application.
12.3.5 Dairy products
Compartmentalised machine-erected trays are typically used for multipacks of
plastic yoghurt pots. The solid board design is preferred as the corrugated fibreboard
equivalent has a larger area on account of the thickness of the sides. This difference
can be critical in supermarket shelf display.
12.3.6 Footwear
Solid board is used in shoe box packaging, alongside folding cartons and
corrugated-fibreboard packaging.
12.3.7 Laundry
In some European markets, large solid board cartons are used for detergent and
soap powders.
12.3.8 Engineering
Products which are heavy, liable to be shifted in transportation, require moisture
protection, and possibly, with protruding parts need the protection of a puncture-
resistant solid board. These boxes can provide rustproof packaging to the Ministry
of Defence (UK) Standard.
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12.3.9 Export packaging
Solid fibreboard packaging is robust and both puncture and moisture resistant.
Where boxes are to be shipped in containers, the box dimensions are designed to
ensure optimum use of the available volume.
12.3.10 Luxury packaging
Litho-printed solid board is used for luxury packaging of products, such as chocolates,
cosmetics and whisky. (Solid board as a material in sheet form is also used by
rigid-box manufacturers, see Chapter 9.)
12.3.11 Slip sheets
Slip sheets can be used in place of wood or plastic pallet bases. The items are
assembled on a sheet of solid board, known as a slip sheet, shown in Figure 12.6.
In order for a fork-lift truck to move such a unit load, it has to operate with a system,
known as a Quick Fork Mount (QFM) which grips a protruding edge of the slip
1000 75
1200
75
Figure 12.6 Slip sheet. (Reproduced, with permission, from Kappa Packaging.)
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
sheet so that it can pull, and subsequently push, both the sheet and the stacked load
onto a platform attached to the truck (FOPT, 1996).
For a unit load size of 1000mm × 1200 mm, the protruding edge needs to be
between 75 and 100 mm wide. This flap is pre-creased so that it can be easily
folded against the side of an adjacent load. Depending on customer requirements,
protruding edges can be specified on one side, two sides opposite, two sides
adjacent, three sides or four sides.
Slip sheets can be made from three plies of kraft with a combined grammage
of 960 g/m
2
. They are also made using 100% recovered fibre at a grammage of
1200 g/m
2
, and with kraft outer liners and recovered-fibre middle plies. The use
of kraft provides a stronger sheet and one that is possible to re-use.
Polyethylene-lined board and hard-sized board can be specified for use in wet/
damp conditions. The presence of PE improves load stability by increasing the
coefficient of friction of the surface of the slip sheet.
An anti-skid varnish can be applied to the slip sheet to assist load stability, but
this is only effective where a similar varnish is applied to the cartons forming the
unit load.
Similarly, thinner sheets, without flaps, are used as layer sheets, to assist the
sweeping of cans, plastic and glass containers at the container in-feed on packing lines.
It is superior to corrugated board for this purpose as it does not indent with the shape
of the upturned container. Solid board sheets are also used as pallet top boards.
12.3.12 Partitions (divisions and fitments)
These are interlocking pieces, divisions or partitions of solid fibreboard, which are
used to create cells in a case or a box wherein individual items of packaging
and packaged products can be placed. The solid board is cut and the fitments or
divisions are interlocked and folded flat for storage and shipment.
Divisions used in this way protect the products by restraining them from
movement rather than by cushioning. Typical examples, including sheets which fit
over bottles to restrain movement, are shown in Figure 12.7. Restraining in this
way is particularly important for glass packaging, for example glass containers and
bottles of wines, spirits, liqueurs, beer, etc. Divisions also protect labels on glass
and plastic bottles from damage due to scuffing during transportation.
Divisions are also used in the packaging of pharmaceuticals, cosmetics, ceramics,
confectionery, fresh produce and electronic and engineering components. Divisions can
be erected and inserted by hand as shown in Figure 12.8. They can also be erected
and inserted on high-speed packing lines in a sequence shown in Figure 12.9.
Whilst corrugated fibreboard partitions and dividers can also be used, they are
less preferred as they are thicker and require larger dimensions in transit cases.
Another important advantage of solid fibreboard dividers is that they can be
cleanly cut and are, therefore, free from excessive edge dust or fibreboard slivers
and trimmings.
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Figure 12.7 Typical solid fibreboard fitments and divisions. (Reproduced, with permission, from
Kappa Lokfast.)
Figure 12.8 Divisions being inserted by hand. (Reproduced, with permission, from Kappa Lokfast.)
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
12.3.13 Recycling boxes
Waterproofed boxes, with lids, can be used for the collection of waste paper and
paperboard. They are used by some local authorities in UK instead of plastic
boxes. The boxes can be attractively printed to encourage their use and display the
collection calendar dates. They can be used in a variety of situations, for
example kerbside collection schemes and in offices, homes and at supermarkets.
The boxes themselves are recyclable.
12.4 Materials
As already noted, solid board can be made on multi-ply paperboard machines. The
higher thicknesses are made by lamination on a paster. This is a machine which
takes reels of board, usually up to six reels in line, glue laminates them and cuts
them into sheets at the end of the paster machine.
The middle layers are made from recycled paper fibre and are grey in colour. The
moisture resistance is increased by hard sizing. Starch is used to increase strength.
In addition to the use of hard-sized middles, one or both outer surfaces can be
laminated with PE-coated kraft to achieve the best water and water-vapour resistance.
The typical weight of PE applied in this way is 15 g/m
2
. White lined, folding
boxboards and solid bleached (white) board can also be used as required.
Figure 12.9 Sequences in high-speed packing for the glass and other industries. (Reproduced, with
permission, from Kappa Lokfast.)
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12.5 Water and water vapour resistance
Figure 12.10 shows the superior wet resistance of water-resistant solid board
compared with standard solid board and corrugated fibreboard measured over a
24-hour period.
Other key data, supplied by Papermarc Merton Packaging, which demonstrates
that water resistant solid board is significantly better than alternative materials is
shown in Table 12.2.
150
100
50
0
01 5153060
Time (min)
Water resistant solidboard
Standard solidboard
Corrugated
fibreboard
Absorption (%)
120 180 1440
Water absorption rate
Figure 12.10 Graph showing comparison for water absorption over 24 h for water resistant solid
board compared with standard solid board and corrugated fibreboard. (Reproduced, with permission,
from Papermarc Merton Packaging.)
Table 12.2 Comparison of various solid boards
* The boards with a puncture resistance of 6 J are immersed in water for 15 min.
Corrugated Standard solid board Water-resistant solid board
Effect of relative
humidity on rigidity
at 90% RH
60% loss of strength 40% loss of strength 20% loss of strength
Effect of water
immersion on
strength
80% loss after 5 min 80% loss after 60 min 10% loss after 60 min
Effect of water
immersion on
puncture strength*
Reduced from 6 to 2.5 J Reduced from 6 to 5 J —
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PAPER AND PAPERBOARD PACKAGING TECHNOLOGY
As already noted, the water resistance of standard solid board is increased by hard
sizing the middle plies and by PE coatings on one or both outer surfaces.
12.6 Printing and conversion
12.6.1 Printing
Depending on the quality required, printing is carried out on sheets by either
letterpress, offset litho or flexo.
12.6.2 Cutting and creasing
Three methods are available:
•
rotary bending machine bends and slots simple designs, such as 4-flap cases
and slotted bases and lids
•
flatbed cutting and creasing forms using a make-ready
•
rotary cutting and creasing forms have the advantage of incremental cutting
and creasing, and hence does not need the high pressures used with an auto
platen.
12.7 Packaging operation
Solid fibreboard packaging can be supplied either for easy make-up by hand or by
machine.
12.8 Waste management
As noted, solid fibreboard cases are usually one-trip containers after which they
can be recovered and the fibre recycled. Where special conditions apply, such as
box cleanliness and appropriate return transport, solid fibreboard cases can be
folded flat after use and returned to the packer for re-use.
12.9 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 con-
cerned. For details, visit Fefco website.
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Reference
FOPT, 1996, Fundamentals of Packaging Technology by Walter Soroka, revised UK edition by
Anne Emblem and Henry Emblem, published by the Institute of Packaging, p. 347.
Websites
www.fefco/ESBO.org (site includes International Case Code).
www.kappapackaging.com.
www.papermarcmerton.com.
13 Paperboard-based liquid packaging
Mark J. Kirwan
13.1 Introduction
The story of paperboard-based liquid packaging over the last century is a classic
business case study. It contains all the elements from the concept to a successful
worldwide business based on vision, motivation and entrepreneurial drive, utilising
skills in science, technology and commerce.
Technically, the concept perceived around 1900 sought a leak-proof paper-based
container to match the glass and metal containers in common use and to replace
the traditional distribution of milk, whereby it was ladled out into the consumers’
own ceramic containers from churns in the street. In this instance, according to
Gordon Robertson’s account of the early development of paperboard-based
beverage cartons (Robertson, 2002, pp. 46–52) there appears to be no dispute
about where the credit lies for the first successful solution. Though earlier attempts
to solve the problem have been recorded, it was in 1915 that a US patent was
granted to John Van Wormer of Toledo, Ohio, for what was described as a ‘paper
bottle’ and which he called Pure-Pak
®
. It was a folded carton blank, which would
be supplied flat to dairies for the packaging of milk. The concept offered several
important advantages which still apply today – those of savings in delivery, storage
and weight compared with glass bottles.
Glass packaging for milk was well established by this time with equipment for
washing, filling and capping. There were systems for the distribution and recovery
of the bottles. The machinery for forming, filling and sealing the paper bottle still
had to be invented.
The carton blank had to be made into a container with the help of adhesives.
It was then made leak-proof by dipping it in molten paraffin wax. The container
was then filled and the top closed by heat, pressure and stapling, as described in
the articles in Modern Packaging and Popular Science Monthly from the early
1930s. Clearly, considerable engineering development work was necessary to
accomplish the forming, filling and sealing and to do this at reasonable speeds
added to the complexity of what was required. Ex-Cell-O Corporation emerged
as the owner of Pure-Pak
®
and the successful machinery producer. Milk was
packed in Pure-Pak
®
cartons at 24 quart, i.e. 2-pint, cartons per minute in bulk
from 1936.
Pure-Pak
®
was used in Europe after World War II. Initially, the cartons were
imported from the USA for filling. Elopak (European Licensee of Pure-Pak
®
) was
formed in 1957. In 1987, Elopak bought the Ex-Cell-O Packaging Systems Division
and the Pure-Pak
®
Licence (Fig. 13.1).
Paper and Paperboard Packaging Technology
Edited by Mark J. Kirwan
Copyright © 2005 by Blackwell Publishing Ltd