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.

## Contents

* 1 Production
* 2 Properties
* 3 Polymer banknotes
* 4 Notes
* 5 References
* 6 Further reading

## 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. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Garoffolo & Sientek 2009, p. 25.
3. ↑ 3.0 3.1 3.2 3.3 Hardwick & Ghioghiu 2004, p. 6.
4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Innovia Security 2013.
5. ↑ 5.0 5.1 5.2 5.3 5.4 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. ↑ 14.00 14.01 14.02 14.03 14.04 14.05 14.06 14.07 14.08 14.09 14.10 14.11 14.12 14.13 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. http://news.nationalpost.com/2011/06/21/graphic-canadas-new-money-is-polymer-in-your-pocket/.
* de Heij, Hans (May 2002), Durable banknotes: an overview, http://www.dnb.nl/en/binaries/2002 BPC General Meeting Durable Banknotes_tcm47-238246.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". Billetaria (Cash and Issue Department, Bank of Spain) 3 (5): 25. http://www.bcn.gob.ni/billetes_monedas/circulacion/afiches/billetaria_5_ingles.pdf. Retrieved 9 March 2014.
* Hardwick, Bruee; Ghioghiu, Ana (2004). "Guardian substrate as an optical medium for security devices". Note Printing Australia. http://www.polymernotes.org/resources/guardiantmsubstrate.pdf.
* Robertson, Grant (3 December 2011). "Funny money: How counterfeiting led to a major overhaul of Canada's money". The Globe and Mail. https://www.theglobeandmail.com/report-on-business/economy/currencies/funny-money-how-counterfeiting-led-to-a-major-overhaul-of-canadas-money/article554632/?page=all.
* ﻿Life Cycle Assessment of Canada's Polymer Bank Notes and Cotton-Paper Bank Notes﻿ (Report). PE Americas, Tryskele. Bank of Canada. 27 May 2011. http://www.bankofcanada.ca/wp-content/uploads/2011/06/Life-Cycle-Assessment-of-Polymer-and-Cotton-Paper-Bank-Notes_opt.pdf. Retrieved 6 March 2014.
* "Guardian - Facts and figures". Innovia Security. 20 September 2013. http://www.innoviasecurity.com/Resources/Guardian-Basics/Guardian-facts-and-figures.aspx.
* "Guardian substrate issuers". Innovia Security. October 2015. http://www.innoviasecurity.com/uploads/pdfs/Guardian Current Substrate Issuers - Oct15.pdf.

## Further reading

* Guarner, Enrique (April 2009). "Polymer and the printing process". Billetaria (Cash and Issue Department, Bank of Spain) 3 (5): 26–27. http://www.bcn.gob.ni/billetes_monedas/circulacion/afiches/billetaria_5_ingles.pdf. Retrieved 9 March 2014.

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