Frequently Asked Questions

blog_5Caristrap is a textile product, manufactured from high tenacity polyester yarn. It is produced from the same basic material used in the fabrication of tires, conveyor belts and V-belts. Caristrap also makes specialty products based on fiberglass cord, cotton, etc.

blog_5Caristrap is tailor-made for the medium and heavy duty strapping market. It is truly the only material able to replace steel strapping or steel wire. We like to call it “synthetic steel” because it is not steel but it is just like it. It will replace and surpass it in any application you can throw at it. It is as strong as steel without all disadvantages…

  • Safer & Stronger than steel strapping
  • ISO 9001:2000 certified
  • AAR approved
The static measure of the strapping material is Break Strength or Tensile Strength. It is not a usable measure by itself as it does not include the buckle (buckles are always used except for some baling applications where it can be omitted) and as it does not consider the dynamics of typical transportation situations.

Buckle efficiency or joint efficiency is rated as a percentage of the strap strength. It varies from 50% to 100%, typically around 65-75% for polyester corded strap wire buckles and 50% for steel strapping seals. For example, if a strap has 1000lbs (or kg) of break strength and the buckle has a 75% efficiency, break strength retained is 750lbs (or kg). AAR (as per new April 1st, 2012 rules) specifies a min. 75% buckle efficiency.

System strength is the strength of one loop of strap, which includes one full strap on one side of the loop plus one strap /w buckle on the other side. Ex: one loop consisting of 1000lbs strap and buckle at 75% efficiency will result in a system strength of: 1000lbs + (1000lbs x 75%) = 1750lbs.


Energy-to-break is the true dynamic measure of the load carrying ability of any strapping material. It is a combination of tensile strength and elasticity. It is the area under the curve of Load vs Displacement (also called extension or stretch), up to the break point.

Caristrap may have lower theoretical strength than steel but because it has more stretch, it is less likely to break quickly under real life loads – more energy is required before the strap breaks, 2-3 times more than equivalent steel.

Stretch of polyester corded strap is approx. 10-12% vs 3-6% with steel. Why is this important?

Elongation (or stretch) is a desired property. It keeps the strap from breaking under severe impacts. In railroad, truck or ocean transportation, high impacts occur repeatedly. A strap with the proper dose of stretch will work with the load and hold instead of popping and breaking loose like steel does.

Unlike corded strap, plastic has too much stretch (up to 30% with polypropylene). That is why is only works with light duty packaging and not heavy goods.

Memory (or recovery) is the ability for the strap to get back to its to original length after load is applied and released. It is considered 99% on polyester corded strap. Why is this important?

Memory is what keeps loads tight. All non-metallic strapping such as lower cost plastics have some recovery properties but corded polyester has the highest (99% vs 50-60% for nylon or PET). Steel has none.

Caristrap is up to 1/5 the weight of steel strapping. Why is this important?

Because coils need to be transported to follow the strapping requirements (ex. mill yard) or for replacement. Steel normally comes in coils of 100lbs (45 kg) or more. Caristrap coils are substantially lighter, therefore no back problems for the employees and no expensive lifting devices needed to change coils.

Coils can be mounted in a variety of positions to best fit the application; horizontally, vertically, over a conveyor, on a fork lift post, with or without wheel dispenser, etc. Heavy steel coils do not offer same flexibility.

Less weight also means savings in shipping.

The 4 elements that make our product unique

Caristrap vs. Steel

Eliminates expensive corner pads or cushioning No scratching or marring of finished surfaces
1/5 the weight of steel strapping Safety to personnel
No rough or sharp edges No cutting into cartons
No rusting Reduce damage to package contents
Can be tied using knot like twine or rope or can be tied
using buckle and hand tension (without tool)
Economical, Versatile
Elongation and elasticity during severe impact –
strap recovers
Can be re-used for in-plant purposes Salvage – environmentally sound
Customization (color & company logo) Free advertising, corporate branding
Ease of application around irregular shapes Enhance package appearance
Less storage space to store Excellent internal package protection against pilferage
Conforms more readily to packages Saves shipping costs
No damage if strap becomes twisted Strap replacement not required, cost saving
Re-tensionable when used with buckles Strap replacement not required, cost saving
Less time to change coils Cost saving

Caristrap vs. PET

PET tool prices, repair costs, and battery change costs are higher.
PET strapping is NOT user friendly – it is too stiff and can damage merchandise. Stiffness does not mean strength. Caristrap is strong and supple.
PET snaps on impact in cold temperatures.
PET has less memory.
PET Energy to Break is lower than Caristrap.
Caristrap is weather resistant and Energy to Break is much greater.
PET coil is heavier than Caristrap coil.
PET unwinds messily – Caristrap unwinds neatly.
Caristrap is re-tensionable – PET is not.
Caristrap can be printed / dyed.
Caristrap uses cord fibers to increase strength.