One of the main objectives for introducing polymer banknotes is to reduce the level of counterfeiting. In 1988, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Australia, conducted the first research activities in the use of polymer banknotes. According to MIT research, the switch to polymer substrate is the result of an effort to reduce one of the highest rates of counterfeiting among the 20 largest economies.
The research conducted at CSIRO under the leadership of Prof. David Solomon developed non-fibrous hydrophobic polymer of which the banknotes were printed. The polymeric material used was biaxially oriented polypropylene (BOPP). Orientation of the semi-crystalline polypropylene film leads to a more alignment of the molecules thereby preventing diffusion of water vapour. The security features were developed by experts in various fields including; polymer chemistry, nano-technology, surface analysis, spectroscopy, etc. Plastic banknotes have several advantages over paper banknotes, these include: Non fibrous and non-porous; last longer at least four times longer in circulation than paper; harder to counterfeit; printing involves high technology that prevents duplicating the note; and can be recycled.
Major challenges many countries (including Nigeria) are facing using paper banknotes include counterfeiting and environmental issues. As for the environmental problem, polymer banknotes can be recycled and re-use for other applications.
In the early stage of development (1992-1997), the Reserve Bank of Australia (RBA) compared the number of counterfeits in polymer bank notes with those of paper banknotes. It is evident from the chart that the number of counterfeits was dramatically reduced by using polymer banknotes. This however prompted some countries to embark upon using polymer banknotes.
Source: John Colditz, Reserve Bank of Australia – Paper presented at The XIII Pacific Rim Banknote Printer Conference, India 1997
The Reserve Bank of Australia (RBA) attributed the big rise in counterfeiting in 1995 and 1996 to an easier access to colour photocopiers and scanning devices, requiring little technical skill to operate. RBA introduced polymer banknotes in July 1992 and no counterfeit was reported in 4 years.
However, in 1996, a handful of counterfeit reported can easily be identified because they were extremely crude and amarteurised. The major advantage of combating counterfeiting is the incorporation of polymer banknotes with first class cutting-edge security technology including transparent section and specially designed holographic section. Mark Carmey, a Canadian, who introduced the polymer banknotes in Canada, now the Governor of Bank of England said the plastic banknotes could be introduced within a few years in Britain. He stated that the polymer banknotes were designed to be more durable, waterproof and harder to forge than paper money which has been in use for more than 300 years.
Other countries after the top 18 include: Zambia (2003), Guatemala , Hong-Kong , Nigeria (2007), Israel (2008), Nicaragua, Paraguay (2009), Honduras , Dominican Republic , Vanuatu (2010), Costa-Rica, Mozambique, Canada (2011) and Fiji (2013).
Canada may go paperless this November because the country is enjoying the advantage of changing from paper banknotes to polymer banknotes. The Canadian dollars are not fading like the Nigerian naira which fades after a short time circulation.
The threats of counterfeiting in Canada have reduced and the lifespan of polymer banknotes was found to be four times longer than paper banknotes.
The success of polymer banknotes may be attributed to two major materials. The polymer substrate and the ink. The most successful polymer substrate used for banknotes in many countries is biaxially-oriented polypropoylene (BOPP). BOPP films are very popular for various applications due to their unique combination of properties resulted from orientation of the molecules in both longitudinal and transverse directions. Among the properties are: strength, transparency, barrier, sealability, and twist retention.
The choice of BOPP as a polymer substrate for banknotes may be due to the following: gloss and clarity, flex crack resistance, strength, resistance to oil and grease, wrinkle resistance and good barrier to water vapour. Other polymer that has been tested is high density polyethylene with trade name of Tyvek developed by DuPont.
Tyvek, a miracle of science is not a paper, not a film and not a fabric but a combination of all three was developed not for banknotes applications but for other applications. The Tyvek fibre is about seven times finer than human hair and this unique attribute coupled with others may be the reason why The American Bank Note Company decided to develop it as a polymer substrate. Trials using Tyvek as polymer banknotes were carried out in Costa Rica, Ecuador, El Salvador, Haiti, Houduras, The Isle of Man and Venezuela. However, Costa Rica, Haiti and Isle of Man issued banknotes made of Tyvek. It was documented in the literature that those banknotes smudged. Countries using BOPP as the polymer substrate are not having problems with the polymer. Other major problem is the ink.
Polymer banknotes incorporate many security features that are not available to paper banknotes. These include the use of metameric inks. Most of the inks used in banknotes are based on metamerism. They offer some security features because they are not commercially available. Metamerism simply refers to two colour samples that match when illuminated by a particular light source and then do not match when illuminated by a different light source.
Polymer naira banknotes at low denominations were introduced in 2007. The problem we are facing today is fading of the inks. The naira notes may look ugly on fading but the good thing is that they can be recycled and used for various applications. It is certain that the security features in naira notes are excellent, i.e. they are much more difficult to forge. The issue of naira notes fading may be due to either the polymer substrate or the ink. If the polymer film, i.e. BOPP is used and the processing is accurate , then the issue may be due to the ink formulation or the interfacial adhesion between the polymer and the ink.
Unlike in paper banknotes, the ink penetrates the polymer whilst in polymer banknotes it adsorbs on the surface of the polymer. Adsorption in this case is due to the crystallinity of the BOPP material and orientation in both directions further prevents diffusion of the ink. With many countries enjoying the benefits of switching to polymer banknotes, the reasons why Nigeria is not going along the line may be due to some factors: (1) use of wrong polymer substrate (2) use of wrong ink/formulation (3) poor polymer/ink interfacial adhesion. These three problems can be solved in Nigeria without involving foreign company or research groups.
Just about a year ago, the deputy governor of the Central Bank of Nigeria CBN), Mr. Tunde Lemo, emphasised that the CBN had resolved to discontinue printing the naira in polymer notes based on the following reasons: (1) hot environment and there is likelihood of the polymer banknotes and their features been degraded by heat (2) environmental factors.
In fact these are not genuine reasons for phasing out the polymer banknotes. As a polymer scientist close to three decades post-PhD experience, BOPP with average melting temperature of around 164oC (depending on the degree of crystallinity) cannot be affected throughout the lifespan of the banknotes. Many countries with similar environmental conditions as Nigeria in Asia and South America with BOPP as polymer substrate do not experience what Mr. Lemo claimed to be one of the reasons to discontinue the use of polymer banknotes. However, those countries (e.g. Costa Rica and Haiti) that use Tyvek as the polymer substrate do have equatorial weather conditions. The second reason given is not also the case as the polymer banknotes can be recycled and reuse for other applications.
The main reason may be non-technical as Mr. Lemo (THISDAY, 12th September, 2012) later indicated that the scandal-hit Securency International Pty Ltd which print the banknotes always force CBN to pay any amount they want. The Securency company accused of bribing officials in Asia (may be Africa as well) was acquired by Allens in alliance with Lintakers on 28th Feb. 2013. With such acquisition, the company may now be free of scandal. Nigerian government may now re-negotiate with the company. However, this is not good for the country.
What we need in this country is research. I am not sure if CBN has a research facility to conduct basic or applied research to solve the problems. Areas that we need to carry out the research include the choice of BOPP with correct orientation (2) Choice of ink with correct formulation (based on metamerism) (3) study on polymer/ink interfacial adhesion, etc. Interfacial adhesion between the polymer substrate and ink may be a leading factor contributing to fading of our polymer currencies. Therefore, adhesion at the interface needs to be improved so that the polymer currencies can last long without fading.
The people in CSIRO in Australia conducted research that lead to the global acceptance of polymer banknotes. Most of the countries using polymer banknotes are now conducting research to ensure they produce their currencies locally. It is time for our government to assemble scientists who can carry out research that will prevent us from wasting resources by paying foreign companies to do our work for us. With the inception of Dangote Petrochemical Company, research activities may be conducted in this gigantic company. The Dangote Petrochemical Company when fully in service may be competing with the best petrochemical giants across the globe, e.g. BASF (the largest), DuPont, Sumitomo, Dow, Idemitsu, Chevron, ExxonMobil, etc). Dangote petrochemical company may develop a better polymer substrate at low cost depending on research as conducted by the Australians at CSIRO. CSIRO never stopped their research activities because they believe there is always room for improvement.
Finally, I am appealing to the Governor of the Central Bank of Nigeria, Mallam Sanusi Lamido Sanusi, and his deputy not to discontinue the use of polymer banknotes due to the advantages to be gained on the long run. They are cost effective because they last long and they contain some security features that are difficult to counterfeit.
My dream is to see all our currency denominations change into polymer banknotes. Paper notes after a short circulation become dirty and create environmental problems. Nigeria needs to move forward in the areas of science and technology. Most countries are introducing polymer banknotes and if our government can fund research activities on the use of polymer banknotes, we may be producing our own polymer currency locally.