When you need to secure loads for transport and storage, choosing the best strapping materials can be a challenge. Polypropylene and polyester are the two most popular plastic strapping materials.
Understanding the differences between the two materials, and how to securely tension them, ensures that you strap your loads efficiently. Your goods will arrive at their destination in good condition, without damage.
Polypropylene (PP) strapping and polyester (PET) strapping: what’s the difference?
The major difference between these two types of plastic strapping is that PET strapping is tougher: it’s used to secure heavier loads than PP strapping.
Both popular forms of plastic strapping can be tensioned and sealed for packaging in a variety of ways: manually; via a battery-operated machine; or for high-volume situations, via a heavy-duty semi-automatic or automatic strapping machine.
Let’s look at the properties of the two types of plastic strapping in more detail.
Popular polypropylene (PP): an excellent general-purpose strapping material
The term “poly” strapping can be used for either polypropylene strapping or polyester strapping. The same tensioning and sealing tools can be used for both. However, be guided by your supplier to choose the best tools and options for your applications.
PP strapping is widely used, because it’s both economical and general-purpose. Available in several grades for either manual or machine application, PP elongates up to 10% when tensioned, offering secure strapping. However, it loses some tension after sealing and won’t recover tension.
It’s used for light to medium strapping and bundling in many industries, including the food industry. You can use it to secure individual packages, as well as to secure loads to pallets.
However, it’s not a suitable strapping option for loads which need to travel long distances, or for loads which will be unloaded and reloaded. Nor is it appropriate for heavy loads, such as bricks in the construction industry.
Although it can be used at various temperatures, and is moisture resistant, polypropylene strapping shouldn’t be used for long-term outdoor storage, because it’s affected by UV light and will ultimately split.
Polypropylene strapping can be tensioned and sealed using most methods: manual, or via machine. When securing loads to pallets with PP strapping, consider using edge protectors to spread the tension and avoid product damage.
After use, polypropylene strapping can be recycled.
Polyester (PET) strapping: reliable for heavy loads
Used in many industries as a safe and economical alternative to steel strapping, polyester strapping is used for large and medium to heavy loads, in industries such as the timber and construction industries.
When compared with steel strapping, polyester (PET) strapping has many benefits.
In summary, it is:
- Safer to use and lighter than steel strapping;
- Recyclable as many times as needed;
- High-performance: it stays tight when loads expand and then contract;
- More economical than steel strapping.
Polyester strapping is available in different grades for different purposes. It’s also available in composite and woven forms, in which strands of polyester yarn are bonded together via adhesives.
These bonded forms of PET offer even more strength and reliability. They’re used for applications such as shipping cargo over long distances, over long periods of time. Polyester strapping expands and contracts with its load, which ensures that loads won’t shift.
Bonded forms of PET strapping are also used to securely ship expensive cargos for industries like the automotive and electronics industries.
How to tension and seal plastic strapping around packaging and loads
Many different types of tensioning tools are available, as well as a vast choice of seals for strapping. If you’re unsure of what you need, get advice to help you to choose the best tools and seals for your applications.
For basic tensioning and sealing of plastic strapping, you need:
- A tensioning tool; and
- A buckle or seal.
The easiest way to secure plastic strapping is via a manual poly tensioning tool. These are both easy to use and convenient: you can use them anywhere. These tools are so basic that no training is required, but do read the manual before using your tool.
It’s a simple operation. The strap is fed through the tensioning tool, then it’s applied around the load. You apply your chosen tension.
Once your strapping is fully tensioned, you can apply your chosen seal, then grip and tighten the seal with a seal crimping tool. Finally, the strap is cut by the tensioning tool: your package or load is now secure.
Although using a manual tensioning tool is easy and convenient, it takes time. Battery-powered strapping tools save time, and may save costs as well. They can be used for both polypropylene and polyester strapping. A battery-powered strapping tool tensions, seals, and cuts your strapping in a single operation, sealing the strap with a friction weld.
Unsure what type of plastic strapping tensioner you need?
Get advice from your supplier. Many options for tensioning and sealing your strap may be used. Your strapping and packaging supplier will ensure that you choose the best for your applications.