Technical Resources Area

Fencing

Potable Water Pipes

Abrasion Resistance

PPA 571 in Construction Projects

How good is the Corrosion Protection offered by Plascoat PPA 571?

The corrosion protection offered by Plascoat PPA 571 is second to none. Salt spray testing to ASTM B117 has exceeded 20,000 hrs with no blistering, cracking, corrosion or flaking. Even if damaged, under-film corrosion from a scribe tested to ASTM B117 for 1000 hrs on suitably pre-treated steel is likely to be between 0 and 0.5mm. Loss of adhesion on testing to ASTM D 3359 – A is zero.

The UV resistance of Plascoat PPA 571 is excellent. After 2000 hrs QUV (ASTM G53) or Xenon arc (ASTM G26), we would expect to see no significant change in color, gloss or mechanical properties. Samples have also been tested in Florida for 5 years at 45 degrees to the sun by the sea – again showing no significant change.

In real life however the performance of PPA 571 coatings tend to reflect or even better this – some of these examples are given below:

Fencing

Fencing is the largest area where PPA 571 coatings are used. The main areas are the Middle East, the US and Australia – for chain link, framework, ornamental and security fencing. The coating meets the requirements of ASTM F1063, 668 and 626.

In the Middle East such coatings are now widely specified, as they have to withstand not only the harsh climate of high UV and heat, but also the sand storms in the desert and the coastal environment. Polyester, galvanized and PVC coatings do not survive long in these conditions and have to be regularly replaced. The picture on the right, however, shows one of the earliest fences coated in Plascoat PPA 571 erected about seven years ago in Dubai. It is inspected regularly and still looks like new with no corrosion whatsoever. The PVC coating nearby is already deteriorating badly.

Now many, many miles of border fencing in the Middle East have been coated in Plascoat PPA 571 both through the desert and by the sea. Since such coatings started in 1994 there have been no failures.

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Fence in Sweden coated in PPA 571

After 10 years

In the US one of the major fencing manufacturers amongst others has converted to the use of functionalized polyolefin coatings such as PPA 571. They advertise that the salt spray corrosion and the abrasion is half that of standard coatings and the fading 1/20^th

Polyester soon after erection of the fence in the UK

Plascoat PPA 571 after 4 years in the UK

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The corrosion problems in Queensland, Australia have to be seen to be believed.

The picture on the right shows an example of aluminum fencing coated in polyester after just 18 months by the sea in Brisbane, Australia where it is both hot and salty.

The second photographs show the same fence recoated in Plascoat PPA 571 after a similar period of time

Potable Water Pipes

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Potable Water Pipes

Thermoplastic functionalized polyolefin alloys such as PPA 571 have been used for coating of water pipes for many years. The coating has a wide range of potable water approvals including NSF61 and conforms to the requirements of FDA food contact. One of the earliest (1990) was for the water distribution in Gothenburg in Sweden (left). This was monitored by the Swedish Corrosion Institute. Firstly, since the installation there has been no incidence of leakage whatsoever.

Secondly the Swedish Corrosion Institute dug up the pipes after 10.85 (11) years in the salty clay soils around Gothenburg. All of the pipes were deliberately damaged before they were laid. These are the results after 11 years:

Rusting Zero
Blistering Zero
Cracking Zero
Flaking Zero

Spread of deliberate defects (left)

From scratch Zero
From circular hole Zero
From blow mark Zero

Adhesion 100% (in fact the adhesive used in the test failed first!)

These results have indicated to the Gothenburg Water and Sewage Works a lifetime for the pipes in the ground of over 200 years

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The experience in Sweden has spread to other parts of the world. Principally, the UK, Australia, New Zealand and the Middle East. Plascoat PPA 571 is also used in the Swiss Alps to carry water for drinking and for snow making to the pistes and restaurants.

In the USA the authorities in Seattle, where the soil is similar to Sweden called on their advice and much of the pipe in the local area and particularly 21,000 ft at Terminal 18 of the port has been coated in Plascoat PPA 571. They too examined the ductile iron pipe after five years and found it to be “as new” whilst the PVC tape wrap had already deteriorated (above).

Plascoat PPA 571 is also used for their chemical and abrasion resistance in slurry and chemical pipes. They have been used in Washington and the Pacific North West in general for gas pipes and for the internal lining of sewage pumps and fittings carrying grit and gravel (see above). Again 1 and 3-year tests showed no wear at all.

The figure left shows a pipe being laid in the Arizona Desert replacing stainless steel for a ferric cure line in a copper leaching operation. The internal lining must withstand sulfuric acid, chlorides and slurries whilst the outside must withstand UV rays and temperatures in excess of 110ºF. After 3 years, the pipes are reported to be “like new”.

Abrasion Resistance

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Abrasion Resistance

We have already had a few examples of the abrasion resistance of PPA 571 coatings – the resistance to sand abrasion in the desert and to slurry in pipes.

The picture on the right is of a children’s playground at the Jumeirah Beach Hotel in Dubai coated in PPA 571. This is one of the few 6 star hotels in the world and since its installation 5 years ago, 25000 children have played on this playground. The hotel reports that after this pounding the coating is still “like new”. In fact they willingly gave us this photograph to show the point.

In Sweden again the PPA 571 coating is being evaluated for road culverts to carry salt and grit from the roadside in winter. It has been tested to ASTM A 926-94, which subjects a coated cylinder to a number of cycles in a mixture of salt and grit – like a washing machine. After one million cycles all other coatings – which included fusion bonded epoxy and galvanizing – were completely stripped. With PPA 571 over half the coating still remained. No other coating met this performance!

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Plascoat PPA 571 has also been trialled for skateboard parks in France. The coating is to replace stainless steel. After one year the contactor was “staggered” by the results. Not only did it provide excellent resistance to abrasion and corrosion but also gave a very good “ride” and provided some degree of safety due to its soft rubbery qualities. In addition the owners were particularly pleased with he fact that graffiti can be easily wiped clean

Finally, PPA 571 coatings are also used in automotive under-body applications, not only for the corrosion protection but also because they can pass the stone chip tests at only 16 mils. These coatings are now starting to be used and specified by Nissan, Renault and General Motors amongst others (SAE J400).

Cart coated in liquid paint after 18 months use

Cart coated in PPA 571 after 18 months use

The Use of Functionalized Polyolefin Coatings in Construction

The Use of Functionalized Polyolefin Coatings in Construction

There are many, many other applications where Plascoat PPA 571 coatings are used ranging from electrical junction boxes to stadium seating and from cable supports to the coating of submersibles, but the other large market in construction.

The primary reasons why such coatings are used by the construction industry are the corrosion protection that can be offered – particularly near or in the sea – and the fact that graffiti can be wiped clean.

Top bars coated in PPA 571 12 years ago

Red handrails recoated in polyester 3 times

No corrosion or loss of adhesion after 12 years

The pictures above show an early example coated about 12 years ago. It is a footbridge over a sea creek in northern Spain. The authorities originally wanted the coating to stop vandals carving their names on the structure but in the event it has proven to be an excellent test site for PPA 571. It has of course been subjected to a salty atmosphere in sun and rain over 12 years.

The green structure was coated in PPA 571 in 1990 whilst the red handrails were originally polyester coated. You can see that the PPA 571 coating still looks like new whilst the handrails have had to be repainted three times. In addition here is an area that was deliberately uncoated. You can see that after 12 years by the sea there is no under-film corrosion or blistering.

Other examples that have shown the long-term benefits of Plascoat PPA 571 include suspension bridges, balustrading, bus shelters, street furniture, construction piles, tanks, fire extinguishers, school furniture in the Caribbean, battery boxes, fan-guards, signposts etc.

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These photographs above show two telephone boxes near the sea in Melbourne, Australia. The expanded mesh in one was originally coated in blue polyester in 1996 whilst the other was coated in Plascoat PPA 571. The photographs were taken this year (2002 - after 6 years). It is clear that all the blue polyester coating on the grill has now been lost whilst the PPA 571 still looks smart and glossy. There is no corrosion.

Finally, again in Sweden the Swedish Corrosion Institute has monitored the lampposts in Stockholm over the last 11 years. They monitored 16 different types of coating both above ground and below ground and at the ground level where dogs unfortunately can go. The coatings included polyester, nylons, epoxy urethane, tape, acrylate etc. Only three were found to be suitable for a lifetime of 50 years – a rubber coating, aluminized epoxy urethane and Plascoat PPA 571!

On the tropical island of La Réunion in the Indian Ocean, surfing waves and cyclones regularly crash over the shore. These lampposts were coated in Plascoat PPA 571 and erected in 1999. The pictures were taken in 2002. The coating still looks perfect.

Lampposts in Bilbao, Spain after 5 years

Summary

In summary the advances in thermoplastics over recent years combined with the improvements in grinding technology have enabled functionalized thermoplastic powders such as Plascoat PPA 571 to be more available for both fluid bed and electrostatic spraying. In addition 12 years of laboratory testing and field experience has shown that such coatings really can provided very long term corrosion protection and abrasion resistance even in very harsh and salty environments as well as having the advantages of food and water approvals, no TGIC, no phthalates, no halogens, no VOCs, no isocyanates, very low toxicity on burning and that graffiti can be wiped clean.

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Main technical documents

PPA 571 - Longevity

Plascoat Systems Ltd.

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