This article is about the paper-based material used to make boxes. For the product made of wood fibers, see fiberboard
Corrugated boardCorrugated fiberboard, corrugated cardboard, or corrugated is a type of packaging material consisting of a fluted corrugated sheet and one or two flat linerboards.[1] It is made on "flute lamination machines" or "corrugators" and is used for making corrugated boxes. The corrugated medium sheet and the linerboard(s) are made of kraft containerboard, a paperboard material usually over 0.25 millimetres (0.01 in) thick.
History
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Corrugated (also called pleated) paper was patented in England in 1856, and used as a liner for tall hats, but corrugated boxboard was not patented and used as a shipping material until 20 December 1871. The patent was issued to Albert Jones of New York City for single-sided (single-face) corrugated board.[2] Jones used the corrugated board for wrapping bottles and glass lantern chimneys. The first machine for producing large quantities of corrugated board was built in 1874 by G. Smyth, and in the same year Oliver Long improved upon Jones' design by inventing corrugated board with liner sheets on both sides,[3] thereby inventing corrugated board as it came to be known in modern times.
Scottish-born Robert Gair invented the pre-cut paperboard box in 1890 – flat pieces manufactured in bulk that folded into boxes. Gair's invention resulted from an accident. He was a Brooklyn printer and paper-bag maker during the 1870s. While he was printing seed bags, a metal ruler used to crease bags shifted in position and cut them. Gair discovered that by cutting and creasing in one operation he could make prefabricated paperboard boxes. Applying this idea to corrugated boxboard was a straightforward development when the material became available in the early 20th century.[4][5]
The corrugated box was first used for packaging glass and pottery containers. In the mid-1950s, the corrugated fiberboard case enabled fruit and produce to be shipped from farm to retailer without bruising, improving the return to producers and opening export markets.
Properties
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Several properties and characteristics can be measured for corrugated board. Some of these include:
Corrugated fiberboard is anisotropic; many of its properties are highly directional. For example, edge crush, bending stiffness, tensile, and surface characteristics are different, depending on the orientation to the flutes and the machine direction of manufacture.
Manufacturing
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Main flutes for corrugated fiberboardCorrugated board is manufactured on large high-precision machinery lines called corrugators, usually running at about 500 feet per minute (150 m/min) or more. These machines, over time, have become very complex with the objective of avoiding some common problems in corrugated board production, such as warp and washboarding.
The key raw material in corrugating is paper, different grades for each layer making up the corrugated box. Due to supply chain and scale considerations, paper is produced in separate plants called paper mills. Most corrugating plants keep an inventory of paper reels.
In the classical corrugator, the paper is softened with high-pressure steam. After the board is formed it is dried in the so-called dry-end. Here the newly formed corrugated board is heated from the bottom by hot plates. On the top, various pressures are applied by a load system on the belt.
The corrugated medium is often 0.026 pounds per square foot (130 grams per square metre) basis weight in the US; in the UK, a 90 grams per square metre (0.018 lb/sq ft) fluting paper is common. At the single-facer, it is heated, moistened, and formed into a fluted pattern on geared wheels. This is joined to a flat linerboard with a starch based adhesive to form single face board. At the double-backer, a second flat linerboard is adhered to the other side of the fluted medium to form single wall corrugated board. Linerboards are test liners (recycled paper) or kraft paperboard (of various grades). The liner may be bleached white, mottled white, colored, or preprinted.
Common flute sizes are "A", "B", "C", "E" and "F" or microflute. The letter designation relates to the order that the flutes were invented, not the relative sizes. Flute size refers to the number of flutes per linear foot, although the actual flute dimensions for different corrugator manufacturers may vary slightly. Measuring the number of flutes per linear foot is a more reliable method of identifying flute size than measuring board thickness, which can vary due to manufacturing conditions. The most common flute size in corrugated boxes is "C" flute.
3
⁄16
108 ± 10 4.8 B flute 47 ± 31
⁄8
154 ± 10 3.2 C flute 39 ± 35
⁄32
128 ± 10 4.0 E flute 90 ± 41
⁄16
295 ± 13 1.6 F flute 125 ± 41
⁄32
420 ± 13 0.8Corrugated fiberboard can be specified by the construction (single face, singlewall, doublewall, etc.), flute size, burst strength, edge crush strength, flat crush, basis weights of components (pounds per thousand square feet, grams per square meter, etc.), surface treatments and coatings, etc. TAPPI and ASTM test methods for these are standardized.
The choice of corrugated medium, flute size, combining adhesive, and linerboards can be varied to engineer a corrugated board with specific properties to match a wide variety of potential uses. Double and triple-wall corrugated board is also produced for high stacking strength and puncture resistance.
Most corrugators are two knife corrugators, which means that they can produce two different sheet lengths side-by-side. This leads to an optimisation problem, known as the cutting stock problem.
Box manufacture process
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Box design
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Packaging engineers design corrugated boxes to meet the particular needs of the product being shipped, the hazards of the shipping environment (shock, vibration, compression, moisture, etc.), and the marketing needs of retailers and consumers.
The most common box style is the Regular Slotted Container (RSC). All flaps are the same length from the score to the edge. Typically, the longer major flaps meet in the middle and the minor flaps do not. However, with the rise of E-commerce and a more competitive retail environment, box designs are becoming more dynamic and functional, straying away from typical shipping box designs.
The manufacturer's joint is most often joined with adhesive but may also be taped or stitched. The box is shipped flat (knocked down) to the packager who sets up the box, fills it, and closes it for shipment. Box closure may be by tape, adhesive, staples, strapping, etc.
The size of a box can be measured for either internal (for product fit) or external (for handling machinery or palletizing) dimensions. Boxes are usually specified and ordered by the internal dimensions.
Regular Slotted Container (RSC)
RSC blank showing score lines, slots, and manufacturer's joint at the leftmost edge
Box maker's certificate
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A box maker's certificate is typically printed on what will become the underside of the boxA box maker's certificate (also known as "box certificate", or "box certificate of maker") is a seal printed on an outside surface, typically the bottom of the box, that includes some information about how strong the box is. The certificate is not required, but if used, it implies compliance with regulations relating to the certificate.[8] Significant information includes:[9][10]
Manufacturing
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Boxes can be formed in the same plant as the corrugator. Such plants are known as "integrated plants". Part of the scoring and cutting takes place in-line on the corrugator. Alternatively, sheets of corrugated board may be sent to a different manufacturing facility for box fabrication; these are sometimes called "sheet plants" or "converters".
The corrugated board is creased or scored to provide controlled bending of the board. Most often, slots are cut to provide flaps on the box. Scoring and slotting can also be accomplished by die-cutting. Along with the print being produced on the box in these plants. These conversions are produced on different machines, depending on the conversion being made: "Flexo Folder Gluers (FFG)", "Rotary Die Cutters (RDC), "Printer Slotters" or " Printing Presses".
Single-face laminate
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A limitation of common corrugated material has been the difficulty in applying fine graphic print for informative and marketing purposes. The reasons for this stem from the fact that prefabricated corrugated sheets are relatively thick and spongy, compared to the thin and incompressible nature of solid fibre paper such as paperboard. Due to these characteristics of corrugated, it has been mainly printed using a flexographic process, which is by nature a coarse application with loose registration properties.
A more recent development popular in usage is a hybrid product featuring the structural benefits of corrugated combined with the high-graphics print of lithography previously restricted to paperboard folding cartons. This application, generally referred to as "Single-Face Laminate" (SFL), begins its process as a traditional fluted medium adhered to a single linerboard (single-face), but in place of a second long-fibered liner, a pre-printed sheet of paperboard such as SBS (solid bleached sulfate) is laminated to the outer facing. The sheet can then be converted with the same processes used for other corrugated manufacturing into any desired form.
Specialized equipment is necessary for the material construction of SFL, so users may expect to pay a premium for these products. However, this cost is often offset by the savings over a separate paperboard sleeve and the labor necessary to assemble the completed package.
Recycling
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Used boxes bundled for recyclingOld corrugated containers (OCC) are an excellent source of fiber for recycling. They can be compressed and baled for cost effective transport. The baled boxes are put in a hydropulper, which is a large vat of warm water for cleaning and processing. The pulp slurry is then used to make new paper and fiber products.
Mill and corrugator scrap, or "broke", is the cleanest source for recycling. The high rates of post-consumer recycling reflect the efficiency of recycling mills to clean and process the incoming materials. Several technologies are available to sort, screen, filter, and chemically treat the recycled paper.
Many extraneous materials are readily removed. Twine, strapping, etc. are removed from the hydropulper by a "ragger".[further explanation needed] Metal straps and staples can be screened out or removed by a magnet. Film-backed pressure-sensitive tape stays intact: the PSA adhesive and the backing are both removed together.[11]
Materials which are more difficult to remove include wax coatings on corrugated boxes and "stickies", soft rubbery particles which can clog the paper maker and contaminate the recycled paper. Stickies can originate from book bindings, hot melt adhesives, pressure-sensitive adhesives from paper labels, laminating adhesives of reinforced gummed tapes, etc.[12][13]
Corrugated fiberboard shredders are now available which convert post-consumer corrugated board into packing/cushioning materials by means of a specialized shredding process.
ASTM standards
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The following standards are in practice among others:
See also
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References
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Further reading
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As important as it is to deliver products safely to consumers, it is equally important that you remain aware of your ecological footprint.
Luckily, there are new alternatives that companies can use to meet both of these needs. For example, Kraft paper boxes are a new trend of eco-friendly cardboard boxes that quickly grow in popularity.
Named after the German word for strength, kraft paper boxes are brown-colored material made from a unique process that is more durable than standard cardboard boxes. The boxes are made from an assortment of natural materials such as:
Natural wood fibers
Recycled Paperboards (solid bleached sulfate.
Sulfur
The percentage of sulfur in the packages is what gives kraft packages their more substantial density. When combined with unbleached kraft paper, it provides another layer of protection while remaining eco-friendly.
And if companies prefer, there are also options to bleach kraft boxes and change the color to white. However, many people prefer the brown color for its more rustic look.
There are currently a few kraft paper bag types dominating the market. All are incredibly useful, and the main difference is the different fibers in the material and the finishes in the production process.
Coated Unbleached Kraft Paper: This is the basic form of kraft paper. It's brown and heavily resistant to ripping.
Coated Kraft Paper: This is the same standard kraft paper with a white bleach additive. The bleach makes the paper very white, allowing for more creative freedom with design choices.
Virgin Kraft Paper: This is made from raw pulp, which is processed natural wood. This is the most potent form of Kraft paper.
Recycled Kraft Paper: This is made from pulp consisting of used cardboard boxes, books, and other materials. It is most commonly used for product boxes, paper bags, and paper cans.
Mixed Kraft Paper: This is made up of a mix of virgin and recycled kraft paper material. It is as strong as virgin paper but is more eco-friendly than its predecessor. It's most commonly used for cardboard envelopes and postage boxes.
Other sustainable products can easily accompany Kraft paper packages to have added benefits. For example, PP film, a type of thermoplastic, can be layered on top of the material to make the case waterproof for consumers.
Kraft packages can also be customized to fit a company's needs. Extra layers can be added or taken away, depending on the type of product. Additionally, openings and back covers can also be placed wherever the customer needs it most.
Typically, the industries that can benefit most from this type of material are "end-use industries" such as:
Pharmaceutical Industry
Foods & Beverages Industry
Cosmetics & Personal Care Industry
Building and Construction Industry
Aerospace Engineering Industry
Automotive Industry
Electronics Industry
More industries recognize the worth of kraft paper material and its eco-friendly aspects and have pushed tons of money into furthering its market.
Currently, the market for kraft paper is worth about $17 million as of 2020, increasing yearly at an average rate of 3.5%. This means that by 2028, it is estimated that the kraft paper market will be worth $22.38 Billion.
Thankfully, the usefulness of kraft paper boxes goes beyond their ecological benefits. Their strong resistance to heat and increased durability make them ideal for transporting delicate goods like glass items and heavy electronic cargo.
Additionally, they also come in a variety of sizes and can be shaped to fit your needs. Such as the option also to have custom inserts made out of the same material that can hold the product in place and prevent it from being damaged.
Not only that, but kraft boxes can mold into tray-shaped or sleeve boxes. These shapes are typically used for lightweight packages and are great for showcasing everything in the box at once.
For companies worried about printing their logo on the kraft boxes don't need to be worried. The material is easy to print on, and there are options to use soy-based ink to further the eco-friendly benefits. If companies want to take it one step further, there are also options for additional add-on directions, such as embossing.
On top of that, businesses can also cut windows into the box if they want their product to be seen by potential customers. There is the option to put a plastic film over that, so the products do not fall out or get stolen, but most companies still prefer to use as little plastic as possible.
One of the most significant selling points for kraft boxes is the sustainable nature of their manufacturing process. While the world continues to struggle with waste management, consumers are expecting more from companies to do their part to combat these environmental issues.
Kraft paper packaging has multiple environmental factors that make it more beneficial than typical cardboard boxes. These include:
Made purely from compost material.
Non-toxic.
Odorless.
Pollution-free.
Low-carbon environmental protection.
National Protection Agency standards approve Kraft paper packages. Kraft paper is also one of the many eco-friendly materials listed on the approved packaging materials list by the FDA for protecting against gamma irradiation exposure.
Kraft paper boxes are essential for fighting against the ongoing problem of plastic pollution. Tons of waste is tossed in the ocean each year to affect marine life or float onto other people's land, which mainly affects marginalized communities.
A study done by Princeton University stated that the problem of plastic pollution is spreading everywhere across the globe than what society had originally thought. Plastic can spread far into porous material and affect waterways and contaminate groundwater supplies.
All of this is throwing our planet into an extreme state of emergency. By regulating single plastic uses and encouraging more industries to use and invest in kraft paper packages, companies can fight back against pollution and show customers they have a soft spot for the environment.
While kraft packages are relatively new material, plenty of research is still done on their effects on consumers. However, a study conducted by the JAMK University of Applied Sciences has found that kraft paper packages positively impact consumer attitudes.
When a company uses kraft packages, it is believed that the product is of higher quality and shows that it is willing to act responsibly towards the environment.
While there are many similar materials as kraft paper, few come close to the versatility capabilities. Kraft packages can be virtually shaped to be helpful in any industry while remaining environmentally friendly.
More consumers are starting to recognize its benefits and actively put their purchasing power towards companies that follow this trend. So it is becoming more vital for businesses of every industry to hop on this trend if they want to remain financially secure and loved by their customers.
For more packaging advice, trends, or ideas, visit Box Genie.
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