Guardian (polymer)

Guardian is the trademark name of a polymer originally manufactured by Securency International,[1] a joint venture between the Reserve Bank of Australia and Innovia Films Ltd. The latter completed acquisition of the former's stake in 2013.

Its production involves gravity feeding a molten polymer, composed of extruded polypropylene and other polyolefins, through a four-storey chamber. This creates sheets of the substrate used as the base material by many central banks in the printing of polymer banknotes.

Production

Polypropylene is processed to create pellets.[2] These pellets are extruded from a core extruder in conjunction with polyolefin pellets from two "skin layer" extruders, and are combined into a molten polymer.[2][3][4] This consists of a 37.5μm thick polypropylene sheet sandwiched between two 0.1 μm polyolefin sheets,[4][3] creating a thin film 37.7 μm thick.

The molten polymer undergoes snap cooling as it passes by gravity feeding through a brass mandrel, which imparts on the thin film many properties, including its transparency.[2] The cast tube material is then reheated and blown into a large bubble using air pressure and temperature.[2] At the base of the four-storey chamber convergence rollers collapse the tube into a flat sheet consisting of two layers of the thin film.[4][2] This creates the base biaxially-oriented polypropylene substrate of 75.4 μm thickness, called ClarityC by Innovia Films.[3][5]

The base substrate is slit as it exits the convergence rollers.[2][4] Four 3-micrometre (0.00012 in) thick layers of (usually white) opacifier are applied to the substrate, two on the upper surface and two on the lower surface.[3][4] A mask prevents the deposition of the opacifier on parts of the substrate that are intended to remain transparent.[6] These overcoat layers protect the substrate from soiling and impart on it its characteristic texture,[7] and increase the overall thickness to 87.5 μm. The resulting product is the Guardian substrate.[4]

The opacifier conversion phase involves the use of resin and solvents, creating volatile organic compounds (VOCs) as by-products that are combusted in a thermal oxidizer.[5] The resulting polymer substrate then passes through a rotary printing press using chrome-plated copper cylinders.[5] After printing, the holographic security foil is incorporated into the base substrate.[5] This is then cut into sheets and transported to the banknote printing companies in wooden boxes as a secure shipment.[5][8]

Properties

Guardian is a non-porous and non-fibrous substrate.[2] Because of this, it is "impervious to water and other liquids", and so remains clean for longer than a paper substrate.[2] It is difficult to initiate a tear on the substrate, which has higher tear initiation resistance than paper.[2]

Polymer banknotes

Guardian is used in the printing of polymer banknotes by many central banks.

It is the base material used for currencies printed by:

Country	Central bank	Currency	Banknotes
Australia[9]	Reserve Bank of Australia	Australian dollar
Bangladesh[10]	Bangladesh Bank	Bangladeshi taka
Brunei[11]	Brunei Currency and Monetary Board	Brunei dollar
Canada[12]	Bank of Canada	Canadian dollar	Frontier Series
Chile[13]	Central Bank of Chile	Chilean peso
Costa Rica[14]	Central Bank of Costa Rica	Costa Rican colón
Dominican Republic[14]	Central Bank of the Dominican Republic	Dominican peso
Guatemala[14]	Bank of Guatemala	Guatemalan quetzal
Honduras[14]	Central Bank of Honduras	Honduran lempira
Hong Kong[14]	Hong Kong Monetary Authority	Hong Kong dollar
Indonesia[15]	Bank of Indonesia	Indonesian rupiah
Israel[14]	Bank of Israel	Israeli new shekel
Malaysia[16]	Bank Negara Malaysia	Malaysian ringgit
Mauritania[14]	Central Bank of Mauritania	Mauritanian ouguiya
Mauritius[14]	Bank of Mauritius	Mauritian rupee
Mexico[17]	Bank of Mexico	Mexican peso
Mozambique[14]	Bank of Mozambique	Mozambican metical
Nepal[18]	Nepal Rastra Bank	Nepalese rupee
New Zealand[19]	Reserve Bank of New Zealand	New Zealand dollar
Nicaragua[14]	Central Bank of Nicaragua	Nicaraguan córdoba
Nigeria[14]	Central Bank of Nigeria	Nigerian naira
Papua New Guinea[20]	Bank of Papua New Guinea	Papua New Guinean kina
Paraguay[14]	Central Bank of Paraguay	Paraguayan guaraní
Romania[21]	National Bank of Romania	Romanian leu
Samoa[22]	Central Bank of Samoa	Samoan tālā
Singapore[23]	Monetary Authority of Singapore	Singapore dollar
Thailand[24]	Bank of Thailand	Thai baht
United Kingdom[14]	Bank of England	Pound Sterling
Vanuatu[14]	Reserve Bank of Vanuatu	Vanuatu vatu
Vietnam[25]	State Bank of Vietnam	Vietnamese đồng
Zambia[26]	Bank of Zambia	Zambian kwacha

In 1993, the Bank of Indonesia issued a commemorative Rp 50,000 banknote and the Central Bank of Kuwait issued a د.ك1 banknote.[4] In 1998, the Bank Negara Malaysia issued a commemorative RM50 banknote,[4] and the Central Bank of Sri Lanka issued a commemorative Rs200 banknote.[27] In 1999, the Northern Bank of Northern Ireland issued a commemorative £5 banknote,[28] and the Central Bank of the Republic of China in Taiwan issued a commemorative NT$50 banknote.[29][4] In 2000, the Central Bank of Brazil issued a commemorative R$10 banknote[30] and the People's Bank of China issued a commemorative ¥100 banknote.[4] In 2001, the Central Bank of Solomon Islands issued a commemorative SI$2 banknote.[31] In 2009, the Bank of Mexico issued a commemorative $100 banknote.[4]

Notes

1. de Heij 2002, p. 6.
2. Garoffolo & Sientek 2009, p. 25.
3. Hardwick & Ghioghiu 2004, p. 6.
4. Innovia Security 2013.
5. Bank of Canada: Life Cycle Assessment of Canada's Polymer Bank Notes and Cotton-Paper Bank Notes 2011, p. 32.
6. Hardwick & Ghioghiu 2004, p. 1.
7. Hardwick & Ghioghiu 2004, p. 2.
8. Robertson 2011.
9. Eu, Chiew & Straus 2006, p. 26.
10. Eu, Chiew & Straus 2006, p. 38.
11. Eu, Chiew & Straus 2006, p. 46.
12. Boesveld 2011.
13. Eu, Chiew & Straus 2006, p. 54.
14. Innovia Security & October 2015.
15. Eu, Chiew & Straus 2006, p. 60.
16. Eu, Chiew & Straus 2006, p. 68.
17. Eu, Chiew & Straus 2006, p. 72.
18. Eu, Chiew & Straus 2006, p. 76.
19. Eu, Chiew & Straus 2006, p. 80.
20. Eu, Chiew & Straus 2006, p. 92.
21. Eu, Chiew & Straus 2006, p. 98.
22. Eu, Chiew & Straus 2006, p. 114.
23. Eu, Chiew & Straus 2006, p. 116.
24. Eu, Chiew & Straus 2006, p. 128.
25. Eu, Chiew & Straus 2006, p. 134.
26. Eu, Chiew & Straus 2006, p. 144.
27. Eu, Chiew & Straus 2006, p. 124.
28. Eu, Chiew & Straus 2006, p. 90.
29. Eu, Chiew & Straus 2006, p. 126.
30. Eu, Chiew & Straus 2006, p. 42.
31. Eu, Chiew & Straus 2006, p. 122.

References

• Boesveld, Sarah (21 June 2011). "Graphic: Canada's new money is polymer in your pocket". National Post. Retrieved 21 November 2011.
• de Heij, Hans (May 2002), Durable banknotes: an overview (PDF)
• Eu, Peter; Chiew, Ben; Straus, Stane (2006). World Polymer Banknotes: A standard reference (2nd ed.). Eureka Metro. ISBN 9834303823.
• Garoffolo, Bruno; Sientek, Paul (April 2009). "Guardian technology starts with the film" (PDF). Billetaria. 3 (5). Cash and Issue Department, Bank of Spain: 25. Retrieved 9 March 2014.
• Hardwick, Bruee; Ghioghiu, Ana (2004). "Guardian substrate as an optical medium for security devices" (PDF). Note Printing Australia. Archived from the original (PDF) on 24 September 2015. Retrieved 8 March 2014.
• Robertson, Grant (3 December 2011). "Funny money: How counterfeiting led to a major overhaul of Canada's money". The Globe and Mail. Retrieved 8 March 2014.
• Life Cycle Assessment of Canada's Polymer Bank Notes and Cotton-Paper Bank Notes (PDF) (Report). PE Americas, Tryskele. Bank of Canada. 27 May 2011. Retrieved 6 March 2014.
• "Guardian - Facts and figures". Innovia Security. 20 September 2013. Archived from the original on 13 October 2014. Retrieved 8 March 2014.
• "Guardian substrate issuers" (PDF). Innovia Security. October 2015. Retrieved 7 March 2016.

Further reading

• Guarner, Enrique (April 2009). "Polymer and the printing process" (PDF). Billetaria. 3 (5). Cash and Issue Department, Bank of Spain: 26–27. Retrieved 9 March 2014.