Foam peanuts (made of extruded polyurethane and manufactured by Free Flow).

Foam peanuts, also known as packing peanuts, are a common loose-fill packaging and cushioning material used to prevent damage to fragile objects during shipping. They are shaped to interlock when compressed and free flow when not compressed. They are roughly the size and shape of a peanut (in its shell) and usually made of expanded polystyrene foam.

[edit] Polystyrene foam peanuts

Polystyrene-based packing peanuts were introduced circa 1965 by Dow Chemical.^[1] Originally made from 100% virgin polystyrene resin, peanuts made from 100% recycled polystyrene have been commercially available since the mid-90s. In the loosefill world, the color and shape tell what it is made of and who made it. Green is 70% or more recycled polystyrene, white is 70% or more virgin resin and pink means anti-stat has been applied; although there are some variations. For example, few green peanuts have pink applied even though they may be sprayed with anti-stat, just as there are expanders who make 100% recycled white peanuts. The most common shapes are the "S" for the STOROpack PelaSpan peanut and the "W" for the RAPAC WingPac peanut.^[2] Or the patented Figure 8 shaped from FP International. The advantage of polystyrene loosefill as a void-fill for shipping is that it is very light (usually around 3 grams per litre/0.17 to 0.2 lb per cu ft) and easy to use. The biggest negative is that it can develop a static charge and that heavy objects tend to migrate to the bottom of the box during shipping, reducing the protection offered.

Polystyrene peanuts may be used and reused many times with little or no loss in protection for the product shipped. They may be reused and recycled at virtually any packing and shipping store.

[edit] Starch-based packing peanuts

In the early-1990s, starch-based packing peanuts were developed as a more environmentally-friendly alternative. The starch in the peanuts comes from crop-based sources rather than petroleum-based polystyrene, and is non-toxic. One of the first brands of biodegradable peanuts, Biofoam, is made from the grain sorghum;^[3] other brands are made from corn starch.^[4] Biodegradable foam peanuts have no electrostatic charge, another benefit over polystyrene. Being biodegradable and nontoxic, they are also safe for humans and pets to ingest accidentally. However, they are not produced in food-safe conditions, and are not recommended for eating. Also, during the manufacturing process, the nutritional value is removed from starch-based packing peanuts. This removes edible components, such as sugars, that would otherwise attract rodents and bugs.^[5] Their main drawbacks compared with polystyrene are lower resilience, higher weight (6.5 to 13g per litre/0.4 to 0.8 lb per cubic foot), dust creation, and higher price. Starch-based peanuts are soluble in water, and polystyrene peanuts are soluble in acetone, but not vice versa.^[6]

[edit] Chemical properties

Because polystyrene peanuts are non-soluble in water, they are also used as a light-weight aggregate in hydroponics. They are also sometimes used to fill beanbag chairs and in a variety of crafts.^[7]

[edit] References

[edit] See also

• Cushioning
• Packaging and labeling