Downsides of pallets produced using recycled materials
10 Jun 2014
Wooden pallets are not a subject many people think about until they think of the environment. In Europe, 90 per cent of pallets are made of wood. In the United States, this figure is 95 per cent.
They are used mostly just once and then discarded. Often they end up in landfill together with many nails and screws that are difficult to remove. Sometimes they may be reused to make tables or other types of simple furniture. However, there is a growing consensus that pallets are a waste of wood resources. A small proportion of used pallets will be recycled into wood fibre and pellets.
Any wood can be used to make a pallet. Pallets can be made of spruce, pine, elm or birch — the usual woods used in Europe. In the United States, half of the pallets in use are made from hardwoods, including oak, maple and walnut, as they produce heavy and strong pallets.
At a time of hardwood shortage in the world timber market, the notion that a disposable wooden pallet is made from precious oak or maple can send many environmentally conscious people into fits of apoplexy.
But wood is a living material. This means it can also house pests and bacteria that will contaminate the goods the pallet is carrying. This has been the experience of food and pharmaceutical companies over the years.
This is how plastic pallets became the environmentally friendly alternative to the wooden variety. Plastic cannot carry contamination, the theory goes. They can be recycled, their proponents claim, and they are much lighter. The plastic can easily house any microchips that are needed to track shipping.
The plastic pallet is gaining market share on both sides of the Atlantic, but what are its disadvantages? Plastic pallet manufacturers also use fire retardants in their products in the same way that wooden pallet manufacturers do. So there is some risk, albeit small, that the chemicals will contaminate any load, as has been the case with wooden pallets.
On the contamination issue, beetles and other insects cannot bore easily into plastic as they do with wood. But this will not stop them from climbing around a load and boring through any thin wrapping material. The contamination issue may be different but is still there in both the plastic and wood pallet cases.
Once a plastic pallet catches fire, it is far more difficult to extinguish than a wooden one. This makes the plastic a greater fire hazard. But what about recycling?
Perils of Recycling
Most plastic pallets are made from high-density polyethylene (HDPE) and polypropylene (PP), as well as the recycled versions of both materials. Once plastic is moulded during heat processing, it loses some of the strength in its molecular structure. The more times it is recycled, the weaker the plastic becomes. So a recycled plastic pallet will break easily over time.
Virgin plastic is more durable and should be used for materials handling in the food and pharmaceutical industries.
The chief advantage of using recycled plastic is its cost. But there is also a downside for the buyer. There is little purpose buying a new consignment of pallets made from recycled plastic if they are brittle and not as string as wood.
Recycled plastic also has a problem with its consistency. The composition of the resin can vary over a short distance. One day the pallet may be a string product, and the next day it could collapse.
It is important for prospective buyers not to see the purchase of a plastic pallet as a cheap alternative to wood. It could become a far more expensive option in the long run.
Used plastic pallets should be matched to the weight of the load they are expected to carry.