Polymer banknotes were developed by the Reserve Bank of Australia (RBA) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and were first issued as currency in Australia in 1988. These banknotes are made from the polymer biaxially-oriented polypropylene (BOPP) which greatly enhances durability of the banknotes. Polymer banknotes also incorporate many security features not available to paper banknotes, making counterfeiting difficult.

Trading as Securency the RBA with Innovia Films, a subsidiary of the UCB group , market BOPP as Guardian for countries with their own banknote printing facilities. Note Printing Australia, a subsidiary of the RBA, prints commemorative banknotes and banknotes for circulation and has done so for 19 countries.

An alternative polymer of polyethylene fibers marketed as Tyvek by DuPont was developed for use as currency by the American Bank Note Company in the early 1980s. Tyvek did not perform well in trials as smudging of ink and fragility were reported problems. Only Costa Rica, Haiti and the Isle of Man issued Tyvek banknotes, however they are no longer produced and have become collectors items.

Development of polymer banknotes

A 10 reais polymer Brazilian banknote released on April, 2000 as a special edition comemorating the country's 500th aniversary

Polymer banknotes were developed to increase the security of Australia's paper currency against counterfeiting. In 1967 forgeries of the Australian $10 note were found in circulation and the RBA was concerned about an increase in counterfeiting with the release of colour photocopiers that year. In 1968 the RBA started collaborations with the CSIRO and funds were made available in 1969 for the experimental production of distinctive papers.

The insertion of an optically variable device (OVD) created from diffraction gratings in plastic as a security device inserted in banknotes was proposed in 1972. The first patent arising from the development of polymer banknotes was filed in 1973. In 1974 the technique of lamination was used to combine materials; the all-plastic laminate eventually chosen was a clear, BOPP laminate, in which OVDs could be inserted without needing to punch holes. The BOPP substrate is processed through the following steps:

• Opacifying - two layers of ink (usually white) are applied to each side of the note, except for an area(s) that is deliberately left clear for creating an OVD;
• Sheeting - the substrate is cut into sheets suitable for the printing press;
• Printing - traditional offset, intaglio and letterpress printing processes are used; and
• Overcoating - notes are coated with a protective varnish.

BOPP is a non-fibrous and non-porous polymer. Compared to paper banknotes, banknotes made using BOPP are more durable, harder to tear, more resistant to folding, more resistant to soil, easier to machine process, and are shreddable and recyclable at the end of their useful lives. On the downside, they cannot be stapled together, they have a slightly less robust feel in the hand due to their slipperiness, and their higher "springiness" makes them resistant to folding, which can cause wallets to spring open unexpectedly.

Security features

The traditional printed security features applied on paper can also be applied on polymer. These features include intaglio, offset and letterpress printing, latent images, micro-printing, and intricate background patterns. Polymer notes can be different colours on the obverse and reverse sides. Like paper currency, polymer banknotes can incorporate a watermark (an optically variable 'shadow image') in the polymer substrate. Shadow images can be created by the application of Optically Variable Ink (OVI) enhancing its fidelity and colour shift characteristics. Security threads can also be embedded in the polymer note; they may be magnetic, fluorescent , phosphorescent, microprinted , clear text, as well as windowed. Like paper, the polymer can also be embossed.

Polymer notes also enable new security features unavailable on paper, such as transparent windows, and diffraction grating.

The transparent window where the OVD is located is a key security feature of the polymer banknote. It is easily identifiable allowing anyone to be able to authenticate a banknote.

Because the polymer bank note contains many security features that cannot be successfully reproduced by photocopying or scanning, it is very difficult to counterfeit. The complexities of counterfeiting polymer banknotes are proposed to act as a deterrent to counterfeiters.

See also Security printing

Adoption of polymer banknotes

Countries with notes printed on Guardian polymer in circulation include, in alphabetical order:

• Australia, Bangladesh, Brazil, Brunei, Chile, Indonesia, Malaysia, Mexico, Nepal, New Zealand, Papua New Guinea, Romania, Singapore, Sri Lanka, Thailand, Vietnam, Western Samoa and Zambia.

Countries that have issued commemorative banknotes (which are not in circulation) on Guardian polymer include, in alphabetical order:

• China, People's Republic of, China, Republic of (Taiwan), Kuwait, Northern Ireland¹, Singapore and the Solomon Islands.

In 1996, Australia was the first country with a full set of circulating polymer banknotes.

In 1999, New Zealand followed suit starting with the $20 note.

In 1999, Romania was the first European country, and the third country in the world, to introduce a full set of circulating polymer banknotes.

In 1999, Taiwan, issued a 10 Yuan note to commemorate the 50th anniversary of the issuance of New Taiwan Dollar.

In April 2000, Brazil released a 10 reais polymer bill in the 500th celebration of the Portuguese arrival in America. The Brazilian Mint printed 250 million banknotes, around half the 10 reais bills available. The bills are considered by some to be less comfortable to use, since they don't fold as easily as the paper ones.

In 2000, China (People's Republic) issued a 100 Yuan note to commemorate the Millennium.

In 2003, Zambia was the first African country to adopt polymer banknotes.

In 2004 it was estimated that there were over 3 billion polymer notes in service. It has also been suggested that the United States and a number of other countries are experimenting with polymer banknotes.

References

• Currency Note Research and Development Project, CSIRO, Division of Chemicals and Polymers Guide to Records
• CSIRO-Polymer banknote information sheet
• Note Printing Australia
• Polymer Banknotes of the World
• Securency

Notes

1. Although the 5 pound Northern Bank polymer banknote was a one-off commemorative issued, unconventionally, in portrait orientation to mark the year 2000, it was in general circulation. It is the only Northern Bank note currently in circulation which will not be affected by the proposed recall of all the bank's notes as a result of the 26.5 million pound raid on its Belfast headquarters on 20 December 2004.