Applications – Woven Polyester Strappings & Lashings

General

Woven polyester strappings and lashings are normally used to unitize cargo loads on pallets or slip sheets and also to tie down unitized cargo loads in containers and trucks . The strappings from 9mm width to 32mm width are used for unitizing cargo loads while those 32mm and above are used to tie down cargo loads .

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  Bundling steel pipes /beams /bars

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  Bundling steel pipes /beams /bars

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  Bundling steel pipes /beams /bars

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  Bundling steel pipes /beams /bars

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  Bundling 25-kg bags

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  Bundling carton boxes

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  Bundling Wire Products

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  Bundling wooden products

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  Bundling drums/tins

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  Bundling drums/tins

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  Tying down drums in containers

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  Tying down equipment /machinery in containers

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  Tying down big bags in containers

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  Tying down cargo loads in flatracks

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  Tying down cargo loads in flatracks

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  Tying down cargo loads in flatracks

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  Tying down cargo loads in flatracks

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  Tying down cargo loads in flatracks

Articles

Using Polyester Cord Strapping For Cargo Load Securing

What is a polyester cord strapping?

Two types:

Uniline - made up of corded polyester yarns held together in a flat strap by PE or glue

Woven - woven from high tenacity polyester yarn

What is it used for?

To bundle or unitised all kinds of load

To secure loads for all methods of transport : by road, rail, sea or air

Advantages Of Polyester Cord Strapping

Cost effective

Safe, light and easy to use

Little or no waste

Tension can be adjusted anytime

Creep Resistant

High system strength

Rot-proof

Properties

High tensile and system strength: 1460 kg linear & 2480 kg system strength

Elastic elongation of 6 - 8%

Shock absorption of 30 – 50 times more than steel strapping

Corrosion resistant

Chemical resistant

UV treated

Temperature resistant : -40 degC to 100 deg C

Buckle closure system

Light weight, soft texture

Easy disposal

Shock Absorption

What is creep?

It is defined as the decrease in tension over time.

System Strength

Linear strength or breaking strength(BS) is determined by tensioning both ends of a strap until it breaks.

System strength(SS) is measured with the strapping in closed loop joined with a buckle

SS = BS x 2 x Joint Efficiency

Example for the 31XTR
SS = 1460 x 2 x 0.85 kg = 2482 kg

Applying The Buckle

Place flat side of buckle against wall or cargo

The prongs of the buckle face right or down

Tension till the prongs close

The Harness System

An approved system for securing cargo in closed container

Specially useful for 210L drums and bulk bags

Easy to set up

Can also be used together with other cargo securing devices like dunnage bags etc.

Step 1 – Vertical Loops

Step 2 – Horizontal Loops

Step 3 – Join Horizontal Loops

Step 4 – Tensioning

Step 5 – Job Well-Done

Typical Specs For Standard Range

Woven Polyester Cord Strappings and Lashings

1)Background

The first US commercial polyester fiber production was by Dupont Company in 1953. At that time, the polyester fibers were primarily used for fabric production.There was a growing movement to develop plastic strappings to replace the steel strappings that were widely used then.

Some time later in the 1950’s , the glue bonded polyester cord strapping was developed .At the early stage , these cord strappings were used for simple bundling of goods .The woven strapping was also developed at about the same time frame.In the 1960’s , the composite strapping was developed .By the 1990’s , cord strappings have made major technical advances to largely replace steel strappings in most applications.

2)Types of Cord Strappings

There are 3 main types of polyester cord strappings depending on their manufacturing processes:

2.1 Glue-Bonded Cord Strappings

The linear polyester yarns are held in band by hot-melt glue .This strapping has a soft and tacky feel . Comes only in natural color.

2.2 Woven Cord Strappings

These are woven from high tenacity polyester yarns and can come in any colour. The woven strapping is soft ,lightweight and flexible.

2.3 Composite Cord Strappings

The linear polyester yarns are co-extruded with polyethylene to produce a stiff strapping band .Only comes in natural colour.

The 3 types of cord strappings are interchangeable in usage. It is just a marketing strategy by manufacturers to diffentiate themselves in order to compete better. Individual customer may have a preference for a particular type based on his individual opinion or usage experience.

3) Properties

All types of polyester cord strappings and lashings share the same properties :

3.1 Safe
It has no sharp edges and does not spring back when cut under tension .

3.2 Strength
It is really strong as steel !

3.3 No damage to products
As it is soft and flexible , it does not damage the product being bundled.

3.4 Rot-proof
It does not rot or stain.

3.5 Lightweight
It is at least 5 times lighter than the corresponding steel strapping.

3.6 Absorbs Shock Better
With about 10% elastic elongation, it can absorb shocks very well .

3.7 High system Strength
When used with a steel wire buckle it provide high system strength and can be retensioned at any time.

3.8 Creep Resistance
Once tensioned it retains its tension.

4) Performance

4.1 Linear Break Strength (Tensile Strength) The most common measure used is the linear break strength where a length of the strapping is pulled till failure .This is following the ASTM standard.

4.2 System Strength The Europeans decided that the system strength is a better measure as it tests the whole loop including the buckle which is how the strapping is used.The system strength shall be double the linear break strength if the buckle is 100% efficient.

4.3 Energy To Break The latest trend is that the energy to break is the most complete measure of strength . This measures the energy required to break the strapping . It is the area under the curve in the force-elongation graph.

4.4 Joint Strength In all applications , strappings have to be joined together into a loop. The joint is also the weakest link in the loop.The common jointing methods are heat seal, crimps , seals and buckles. For the polyester cord strappings , buckles are the only means of forming strong joints.There are two main types of buckles being used for cord strappings and lashings :
i)Wire buckles are used for strappings up to 32mm width.
ii)Welded rectangular buckles are used for lashings of width 32mm and above. Buckles with hooks or cam buckles may also be usedwhen lashings are used to tie down cargo loads for transportation.

The joint strength is normally called the buckle efficiency which is the measured system strength divided by twice the linear break strength and given in percentage.

Buckle Efficiency= (Measured system strength / 2 x Linear break strength) x 100%

The buckle efficiency normally range from 75%- 95% , depending on how well the buckle is designed and produced.

4.5 Creep Strappings are expected to maintain its applied tension around the goods over time. Unfortunately, it is a natural phenemenon for tensioned strapping systems to lose strength over time and this is called creep . It has been shown that the corded polyester strapping with wire buckle system has less than 10% creep and is far superior to other strapping and jointing systems.

4.6 Shock Absorbency The polyester strappings have an elastic elongation of about 8-12 %. During the elastic elongation phase ,the tensioned strapping will return to its original state once the tension is released. In application , this acts as a shock absorber to absorb sudden load and return to the normal state once the shock is over.

5) Accessories

5.1 Tensioners A tensioner (either manual, pneumatic or automatic) is used to tension the strapping looped around the goods .Tensioners come in various sizes to suit the strapping width.

5.2 Wire Buckles The buckles also come in various sizes to suit the width and breaking strength of the strapping .These buckles have either galvanized or phosphate treament finishing. The phosphated buckles (dull blackish color)are slightly moreexpensive but have better slip resistance as the phosphate treatment gives a rough finish to the surface of the buckle.

Can Polyester Strappings Replace Steel Strappings In Malaysia?

1) Background

In the 1980s and 1990s, steel strappings were widely used to bundle goods especially in heavy duty applications. Since then, steel strappings have largely been replaced by plastic strappings which cost less and have better performance. This trend is also largely true in Malaysia especially amongst the larger companies which use imported steel strappings .However, there are still some local companies continuing to use locally produced steel strappings due to the price aberration brought about by government policies.

2) Government Policies On Steel

In order to protect the local steel industry, especially of the flats segment, the government raised the import duties in March 2002 to a maximum of 50% on a total of 199 flat steel products .Companies wishing to import these products were also required to seek special import licences or approved permits(AP). The government also erected some restrictions by imposing ceiling prices for retail purchases of steel billets which are used to make steel strappings.

3)Comparison of steel strappings versus Polyester Cord Strappings

4) Marketing Strategy

In spite of the government policies , the woven polyester strapping is still not more expensive than the steel strapping. So, it is highly probable that the polyester strappings will eventually replace steel strappings in general use. This is no different from what is happening in the rest of the world.

5) Pricing Data for Steel Strapping ( April 2011)

Malaysia
The retail price is about RM3200 per tonne .

5.2 USA
3/4”, 0.015 gauge,2751 ft/coil , 110lbs/coil, price :USD160/coil
www.packagingprice.com

5.3 Australia
19mm width, 45kg/roll , price:AUD118.80

5.4 China
5.4.1 FOB Price : USD620-800/tonne
www.hualude.com

5.4.2 FOB Price: USD750 – 1188/tonne
http://bkleading.en.alibaba.com

Comparison of Woven Polyester Strapping With Composite Strapping

1) Background

Both type of strappings have polyester fibres as their main component .Therefore, their properties and performance are the same . Their manufacturing methods are different and so they look different physically.

The woven polyester strappings are weaved like fabric .This is one of the oldest and most reliable method of production .All lashings for extra heavy duty or safety applications are still made by weaving . The composite strapping is produced by encasing the strands of polyester cord in PE .This made the strapping stiffer and supposed to mimic the steel strapping .It was developed in the 1960s to replace the steel strapping.

2) Comparison

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