Our Plastic Experts have put some information about PP Sack Recycling together for you. Enjoy!
How are PP Sacks Recycled?
It would be great if everybody could agree on a name for PP Sacks, but since that seems to be out of the question, you may recognize them by a different title. Some call them PP Big Bags, Bulk Bags, FIBC’s, Builder’s Bags, Dumpy Bags, Woven Polypropylene or Rubble Sacks. They can come in any colour and are fit for a variety of uses. Whilst PP Sacks are most commonly used in the construction and transport industries, you may be surprised to know that many ‘bags for life’ are essentially just miniature versions.
One interesting fact about PP Sacks is that they are very commonly used for transporting other plastics. When the recycled plastic is granulated it is put in a sack and enters the market for trade.
In the PP Sack Recycling Industry, there are three grades for the material, all of which will affect the value, recycling route and end markets. Grade A, the top grade, means it is clean, very white (can contain blue stitching or handles) and will command the highest market value. Grade B is mostly white, but can contain other light colours, and is generally more used and unclean than Grade A, but wouldn’t be described as dirty. Grade C is more dirty or heavily coloured bags, and has the lowest market value of the grades.
It’s not like putting your weekly bin out...
The PP Sack Recycling process starts like other industrial plastic recycling processes, with the proper collection and treatment of the material. In this instance, most PP Recyclers will demand that the material is compacted into mill sized bales for ease of transport and optimal market value. It’s also traded in large quantities, so generally it is only businesses with a large PP output or the ability to collect and store it over time that are involved in the recycling.
The PP Sacks are likely to have contained anything from chemicals and fertilizers, to sand, gravel or grains, so it is very important that they are cleaned efficiently before being recycled. In fact, this contamination makes PP sack recycling difficult and infrequent. Despite being the single most used plastic packaging material in the UK, only 1% of post-consumer PP ends up being recycled. The message to take from this is that decontaminating PP is extremely difficult and until it can be done cheaply and efficiently en masse, PP Sack recycling will suffer.
The Recycling Process…
The PP Sack recycling process is actually fairly straightforward. The material is collected in mill sized bales and taken to a reprocessing centre. At this location, the bags are sorted, decontaminated and cleaned. Things like zippers and buttons are removed and the bags are shredded into a flakey plastic. The material is then fed into an extruder, which melts it at 240 degrees celsius! In this stage it is formed into small uniformly sized beads, known as granules, which can then be remelted into different products at a later time. It is normal for virgin PP (unused PP rather than recycled) to be added to the mixture, to make it stronger and more valuable.
New technologies are in production to make the process more viable, so that the shocking 1% recycling figure can be improved. One such technology is working on a process that makes decontamination very simple, though it is scientifically complex, tackling the issues at a molecular level using vacuums and heat treatment!
The PP Sack recycling process finishes its loop when the granules are melted and formed into a new product, which can be anything from a dustpan and brush to remote control. The loop can keep going though, as it’s possible to recycle Polypropylene many times!