Corrugated cardboard

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Corrugated cardboard

Corrugated cardboard (also known as corrugated cardboard in Switzerland ) is a pulp product mainly used in the packaging industry that is light and relatively stable in relation to its weight. Corrugated cardboard is one of the most widely used packaging materials. It is mainly used for transport packaging: its market share in Germany is 64% (as of 2015). The manufacture of corrugated cardboard is a complex industrial process; the most important raw material for this is paper.

Corrugated cardboard is created by gluing together at least one smooth and one corrugated paper web (one-sided or one-sided corrugated cardboard). Up to nine paper webs are used to produce corrugated cardboard (multi-wall corrugated cardboard). The corrugation is its decisive characteristic: light paper is extraordinarily strong when it is corrugated or corrugated and glued to smooth paper webs to form hollow volumes. A kind of lightweight construction made of paper creates a stable packaging material.

Many different types of corrugated cardboard and corrugated cardboard packaging are produced depending on the requirements and area of ​​application.

The term 'paperboard' comes from the earlier use of the term 'paperboard' for gluing together.

history

Corrugated paper was patented in England in 1856 and used as an insert for high hats. It was not until 15 years later, on December 19, 1871, that the US Patent Office granted Albert Jones of New York a patent for "improving paper for packaging purposes". So Jones first used curled paper for packaging purposes, namely for wrapping and shipping bottles and glass vials . The American Oliver Long produced real corrugated cardboard for the first time by gluing a smooth paper web to the corrugated paper web patented by Jones. Three years after Jones' development, one-sided (or, for short: one-sided) corrugated cardboard was created. Long received the US patent for this invention on August 25, 1874. Double-sided (today we say: single-wall) corrugated cardboard, with liners on both sides, was the first to be patented by Robert H. Thompson on January 17, 1882 in the USA.

Thompson & Norris , founded in 1875, bought the patents from Jones and Long and developed industrial production of corrugated cardboard, initially in the USA, and from 1883 in London. The first production facility in continental Europe was founded in 1886 near Jülich in the Rhineland, also by Thompson & Norris . Only after the Jones patent had expired in America did American patent holders compete. For the first time, machines for the production of corrugated cardboard were developed on the European mainland.

The first independent German corrugated cardboard factory was founded in 1892 by Fedor Schoen (paper and corrugated cardboard factories Fedor Schoen, Cologne) . He had machines built by the machine manufacturer Wilhelm Richter in Wroclaw according to his own specifications and there he produced one-sided corrugated cardboard in rooms that belonged to his brothers. In 1894, production was relocated to Cologne, the main industrial area in Germany, so that double-sided corrugated cardboard was soon also produced there. In the following years further corrugated cardboard plants and paper mills were founded in Stuttgart , Vaihingen , Berlin , Dresden (1911), Gittersee, Neuss (1919) and Dohna . Corrugated cardboard is still produced at the Cologne (1976–2015 relocated to Pulheim) and Dresden locations.

Wilhelm Richter, who first built a single corrugated cardboard machine in 1895, was the first manufacturer of corrugated cardboard machines (and not C. F. Langston, as claimed in American publications). However, Richter did not build for the general market, but had to undertake to deliver only to Fedor Schoen or only with his approval.

At the beginning of the 20th century, the corrugated cardboard box gradually began to replace the custom-made wooden trays and containers that had been customary in trade, freight and transport.

The first test method (bursting pressure according to Mullen) was introduced in the USA in 1907 for corrugated cardboard too, after it had already been used for paper tests. It was not until 1959 that the Mullen tester was officially recognized in Germany. In Indiana , double-walled corrugated board was produced for the first time in 1916 (double-double). In 1929, the B-wave was added to the previously known A-wave.

numbers

Approx. 275,000 people worldwide are involved in the manufacture, processing and sale of corrugated cardboard; in 2010 there were around 18,000 people in Germany.

In 1991 there were 1650 corrugated cardboard plants in the western world, 661 of them in Europe and 97 in Germany; In 2010 there were 39 companies with 114 plants in Germany. In Europe, Germany ranks first in 2010 with sales of around 9 billion m 2 (which corresponds to around 4.8 million t).

Corrugated cardboard consumption per person in kg in 2007 was:

United States 76
Japan 69
Italy 65
Spain 57
Belgium 55
Austria 55
Germany 55
France 48
Denmark 47
Netherlands 40
Sweden 38
Ireland 36
Great Britain 32

sorts

General

Labeled schematic structure of corrugated cardboard

A distinction is made between different types of corrugated cardboard, types of corrugation and combinations of corrugations. The most common types of waves in the single -wave range are C-wave (medium wave) and B-wave (fine wave) and E-wave (ultra-fine or microwave).

In the double -wave range , wave combinations of BC-wave (fine and medium wave), EB-wave or EE-wave are mainly used. For three-wall corrugated board are ACA (rough wave medium wave rough wave), BAA (fine wave rough wave rough wave), EBC (extra thin fine wave medium wave) or BBC (fine wave fine wave medium wave) common shaft combinations.

The choice of flute combinations in connection with the basis weight and the type of corrugated board base paper (e.g. Kraftliner or testliner as cover paper and, for example, semi-cellulose or Schrenz as paper for the flute ) depend on the product to be packaged and its shipping route and the resulting stresses .

For lighter goods i. d. Usually single and double wall corrugated cardboard use, typically z. B. for products of the food and luxury food industry (consumer goods). Three-wall corrugated cardboard can be used for heavy and sensitive goods, e.g. B. be used for overseas shipping and serve as a replacement for wooden packaging. The goods to be packaged are often capital goods with high weights and special requirements due to unfavorable climatic conditions during the shipping route and at the destination.

In addition to the choice of the flute combination and the base paper type with the corresponding basis weight, the packaging design is also decisive for the stability of the packaging and the protection of the product.

The FEFCO-ESBO code gives an overview of the constructions of standardized shipping packaging. In addition, companies in the corrugated cardboard industry develop individual constructions alone or in cooperation with their customers.

The corrugated cardboard is built up in several layers. For single-wall corrugated cardboard, these are:

  1. Exterior ceiling
  2. Wave run
  3. Interior ceiling

Different types of paper can be used for ceiling and corrugated sheets to achieve the strength values required for the respective application . These papers differ in their proportion of fresh and recycled fibers as well as their area-related mass , the so-called basis weight. Better strength can be achieved through the use of papers with a high proportion of virgin fibers, but also through higher grammages.

species

Wave types
character Wave type (name not standardized) Shaft pitch (mm) Wave height (mm)
O* Graphic wave 1.3 0.3
G Graphic wave ≤ 1.8 ≤ 0.55
N * Graphic wave 1.6 to 1.8 0.4 to 0.6
F. Mini wave 1.9 to 2.6 0.6 to 0.9
E. Fine wave / microwave 3.0 to 3.5 1.0 to 1.8
D. Fine wave 3.8 to 4.8 1.9 to 2.1
B. Fine wave 5.5 to 6.5 2.2 to 3.0
C. Medium wave 6.8 to 7.9 3.1 to 3.9
A. Coarse wave 8.0 to 9.5 4.0 to 4.9
K Maxi wave / imperial wave ≥ 10.0 ≥ 5.0

(* A standard is not available or is in preparation for wave types N and O.)

Waveform

The wave form produced in Germany is the sine wave, also called "round corrugation". The so-called V-profile is less common in Germany.

Double shaft (duplex, combi shaft)

Labeled schematic structure of corrugated cardboard

With double-wall corrugated cardboard (e.g. BC-flute) the structure is as follows:

  1. Exterior ceiling
  2. B wave run
  3. False ceiling
  4. C-wave track
  5. Interior ceiling

In the case of double corrugation, glue is applied to the exposed corrugation crest of the two single-sided corrugated cardboard in a laminating unit and both are glued to one another and a final membrane in the heating section. As an alternative to this, gluing using cold glue is also possible, here the glue is applied to the lower web by a glue unit and the upper web is laminated and fixed by means of pressure until the adhesive force (the tack) is sufficient.

Manufacturing

Corrugated cardboard is manufactured with so-called "corrugators" or simply corrugated cardboard systems (WPA). With such systems it is possible to produce single-layer (simplex), double-layer (duplex) or three-layer (triplex) corrugated cardboard. The paper of the corrugated track is shaped under pressure by means of corrugated rollers and hot steam and glued first to the inner ceiling, then to the outer ceiling; starch glue is used for gluing . A corrugated roller looks similar to a gear wheel in cross section. The curve on the corrugated roller determines the wave shape and height. Most corrugators have a working width of 2,500 mm. Modern corrugator is now also available with working widths of up to 3,300 mm; Under the best of circumstances, they can produce corrugated board at a production speed of up to 400 m / min. That means over 1,300 m 2 / min or 79,000 m 2 / h.

Corrugated cardboard components:

  • Fluting paper
    • Corrugating medium (gray, recycled waste paper with sizing agents)
    • Semi-pulp (deep brown, incompletely digested pulp)
  • Liner paper
    • Schrenz (gray, recycled waste paper)
    • Testliner (gray, recycled waste paper with one-sided coating)
    • Kraftliner (unbleached or bleached sulfate pulp with or without a line)
  • Adhesive
    • Starch glue
    • Water glass glue
    • Stone Hall adhesive
    • No carrier adhesive

BHS Corrugated Maschinen- und Anlagenbau GmbH , which is based in the Upper Palatinate community of Weiherhammer, is the world market leader in the development and assembly of corrugated board systems . This is followed by the Italian company Agnati, the Italian-American competitor Fosber and Mitsubishi Heavy Industries, which is active in numerous industries .

Offset corrugated cardboard packaging

As offset corrugated packaging are offset printed referred corrugated packaging. A printed sheet is glued onto a finished corrugated sheet , which consists of an inner ceiling and corrugation and is cut into sheet-sized pieces at the same time. So-called laminated sheets are produced. The production of MDuplex and triplex is also possible here. To do this, 2 or more lamination units are required in direct succession. The printed sheet acts as the outer ceiling. Offset corrugated cardboard packaging is often found in supermarkets ( POS ) because it sells products very attractively. From 1980 to 2009 a development of trays (4–8 cm high, open-topped cardboard boxes, in which cans, bottles (possibly shrink-wrapped with film) or product boxes stand) and outer boxes at food discounters can be observed: from consistently brown to the outside, then too white inside and later printed on the outside, first in one color, now often in multiple colors, and finishing forms such as hot foil stamping are even used in this segment.

Construction and insulation material

As a composite cellulose element , corrugated cardboard is offered in layer thicknesses between 15 and 340 mm as a construction and insulation material .

The standard size is 125 × 62.5 cm. Sizes up to 550 × 240 cm can be made.

Curvature of corrugated cardboard ( warp )

The curvature of corrugated cardboard, also called warp (from the English verb to warp - to bend , to deform or noun warp - chain, line ), is a common problem in the manufacture of corrugated cardboard. It can essentially occur at two points in time:

The so-called corrugator warp ( corrugator : corrugated cardboard machine ) occurs directly after the production of the corrugated cardboard. It is caused by incorrect machine settings, machine defects and faulty raw materials (raw paper). For the post corrugator warp ( deformation after the corrugated cardboard machine), in turn, incorrect storage of the finished material is the cause: the finished sheets leave the corrugator lying flat and only bulge after a few hours to days. The trigger here are incorrect or unfavorable storage and climatic conditions.

The so-called warps are also classified according to their shape:

Up warp
Two or four edges of the (lying) arches rise and form the cross-section of the arch in the "U" direction.
Down warp
The edges slope downwards. The pile resembles a hill.
Side-to-side warp
If the curvature of the sheets runs transversely to the machine direction, one speaks of side-to-side warp. This form is caused by the different levels of moisture in the ceiling membranes.
End-to-end warp
denotes crooked arcs in the machine direction. The reasons for end-to-end warp are different moisture levels in the ceiling membranes or different web tensions.
S-warp
is characterized by the reversal of the orientation of the warp against the machine direction. Causes can be local differences in moisture levels in the ceiling membrane or incorrect storage.
Twist warp
is in the shape of a corkscrew and can be caused by any of the above.

The curvature of the corrugated cardboard during stacking can be minimized or completely prevented by alternately turning over corrugated cardboard packages (consisting of several corrugated cardboard sheets) and / or inserting intermediate boards.

Processing, special features, accessories, subsequent uses

Archival boxes made of corrugated cardboard

In order to process corrugated cardboard into boxes (= mostly cuboid boxes), after the material has been selected, careful planning of a cutting pattern is required, which takes into account the behavior of the box when it comes to bending, folding, loading and tearing in terms of geometry and strength. The edge, tear-off corners and viewing windows are trimmed. Interrupted cuts make folding easier or define tear lines, but can also be used for simple marking and labeling. The creasing establishes fold lines. Cardboard boxes are usually folded and glued or plugged or stapled. For storage when unfilled, cardboard boxes can be left open at the top and bottom (square tubes with lid flaps) and folded flat around two raised folds, or the bottom - except for one hole - can be closed and still foldable. Sufficiently conical cardboard boxes can be plugged into one another and stacked in this way, non-square-cuboid one in two into one another. Corrugated cardboard packaging is manufactured using a CAD program. Punching tools are manufactured from this program .

Trays for fruit are made stackable using fits: upright flaps at the top fit into cutouts below. Grip slots with the upper edge rounded by bending in the flap allow heavy goods to be carried comfortably (e.g. tube TV sets). Another way of creating handles is to rivet handle tapes made of soft PE or thin, fibrous polyester , for example to boxes for 2 to 6 kg of detergent. There are handles made of PE which - inserted through two holes in the box - hook onto a PE insert on the inside and can be pressed flat from the outside by gently pushing inwards. On six-packs for half-liter beer bottles, there are two types of grip holes in the space between the bottle necks: One horizontally lengthways in an upstanding tab for all four fingers or two perforated tabs that can be pressed into a horizontal surface with a click for the clamp grip only with thumb and forefinger.

In the case of plug-in connections, tuck-in flaps can be provided with a transverse cut on the edge, which clamps after insertion, so that the first time the box is opened leaves a tear or at least a visible kink in the packaging. With snap-in connectors, cleverly shaped sales displays can be stiffened up to a height of two meters. Connections for archive boxes and small furniture should also snap into place.

Cardboard boxes can be designed with removable lids (shoes, copy paper), which can be reused. A lid can be folded down and clicks into place: Examples of this are the packaging for glucose tablets, sports shoes, and cigarettes. Tub-shaped cardboard boxes can be closed very stiffly with a two-surface lid with four lateral tuck-in flaps and possibly a fifth small safety flap (PC motherboards, expensive devices that are to be presented personally and securely packaged again). These are suitable for subsequent use as a dimensionally stable container for books or small items in a backpack.

Corrugated cardboard stacks with ten or more corrugations (the layers and corrugations stand vertically for maximum load capacity) can be used to create very stable and non-slip blocks and bars for cardboard-wood pallets. There are also pallets that are made entirely of corrugated cardboard or mixtures of corrugated and solid cardboard and have similar properties (load-bearing capacity, etc.) as plastic, pressboard pallets or the like. exhibit.

Low fruit crates are very stiff and are equipped with adhesive dots that can be easily torn off by hand so that they take up less space as waste. Presses compact cardboard boxes with a stubble roller or a ram in or in front of a sheet metal container in order to reduce storage and transport requirements. Because of the risk of bodily harm, these facilities were almost completely taken over into the company buildings. Private garbage producers are advised to dismantle or fold cardboard boxes before throwing them into the waste paper container, because some of the valuable fibers are shortened when they are torn or cut. Simple snap-off or hook blades are advantageously used for manual cutting of corrugated cardboard. If you only cut into one layer, a kink line can be defined.

recycling

Corrugated cardboard recycling code

Corrugated cardboard is based on natural raw materials. Corrugated cardboard produced in Germany consists on average of 80 percent recycled material, namely waste paper. The rest are fresh fibers from cellulose, which in turn is made from wood. All corrugated cardboard base papers produced in Germany are predominantly made from waste paper and are therefore allowed to be labeled 'recycled paper'. Papers made primarily from fresh fibers are imported from abroad. The glue used in the manufacture of corrugated cardboard is made from potato, wheat or corn starch. Corrugated cardboard is therefore a material product made from renewable raw materials.

A lot of energy is needed to generate it, mechanical has been generated from electricity for around 100 years, some of it from our own river power plants, for example at the Gratkorn site or the Merckens Schwertberg cardboard factory , while paper mills used to be driven by mill wheels and mechanical transmission. Rivers are used to extract cooling and process water and as receiving waters for waste water. Paper producing companies burn and a. Residual materials in order to gain process heat. The use of waste heat at a lower temperature level than district heating is more likely if the necessary line length for the feed is not too long (<± 10 km) and a long-term delivery guarantee can be agreed.

The return rate of 70% stipulated in the Packaging Ordinance (VerpackV) for packaging made of paper, cardboard and cardboard is far exceeded by corrugated cardboard, because in Germany it is almost completely collected and recycled. Only a small part of this comes from private households who dispose of used corrugated cardboard packaging in the waste paper bins. The vast majority of used corrugated cardboard packaging is mainly used in retail and industrial operations. There they are collected, pressed to save space if necessary, and finally picked up by a waste disposal company. This supplies the waste paper as a raw material to the paper mills, which use it to make paper - including raw paper for corrugated cardboard production.

The closed material cycle works according to market economy principles, since used corrugated cardboard, like the rest of the waste paper, is a sought-after raw material for the paper industry. The RESY recycling system ensures the material reuse of all transport and outer packaging made of paper, cardboard and corrugated cardboard that is marked with the RESY symbol. RESY OfW GmbH is a community of corrugated cardboard manufacturers, waste paper disposal companies and producers of corrugated cardboard base paper. The RESY symbol with the three arrows printed on most corrugated cardboard packaging confirms that this material is recyclable and that it is recycled by the partners of RESY OfW GmbH.

Since 2009 the Verband der Wellpappen-Industrie e. V. (VDW) with the eco-label all users of corrugated cardboard packaging a further label that indicates the favorable ecological properties of this material.

In Austria, those who sell cardboard packaging pay “ARA” contributions to Altstoff Recycling Austria to help finance their disposal. A corresponding ARA license number is stated on invoices.

See also

literature

  • Facts and figures - The most important figures for the corrugated cardboard industry , publisher vdw Verband der Wellpappen-Industrie e. V., edition 2007
  • DIN 55468, Part 1., Packaging materials - Corrugated board - Part 1: Requirements, testing , August 2004 edition

Web links

Commons : Corrugated Cardboard  - Collection of pictures, videos and audio files

Individual evidence

  1. ^ Association of the Corrugated Cardboard Industry. Share of different materials on the market for transport packaging in Germany from 2008 to 2015. https://de.statista.com/statistik/daten/studie/240922/umfrage/struktur-des-marktes-fuer-transportverpackungen-in-deutschland/ (accessed December 21, 2017).
  2. ↑ VDW, Handbook of Corrugated Cardboard, Part 1.
  3. ↑ Waste heat potential in Styrian industry in 2012 see: Gratkorn ( Sappi paper mill ), accessed on July 21, 2014.