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

^ de Heij 2002, p. 6.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Garoffolo & Sientek 2009, p. 25.
^ ^a ^b ^c ^d Hardwick & Ghioghiu 2004, p. 6.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k Innovia Security 2013.
^ ^a ^b ^c ^d ^e Bank of Canada: Life Cycle Assessment of Canada's Polymer Bank Notes and Cotton-Paper Bank Notes 2011, p. 32.
^ Hardwick & Ghioghiu 2004, p. 1.
^ Hardwick & Ghioghiu 2004, p. 2.
^ Robertson 2011.
^ Eu, Chiew & Straus 2006, p. 26.
^ Eu, Chiew & Straus 2006, p. 38.
^ Eu, Chiew & Straus 2006, p. 46.
^ Boesveld 2011.
^ Eu, Chiew & Straus 2006, p. 54.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Innovia Security & October 2015.
^ Eu, Chiew & Straus 2006, p. 60.
^ Eu, Chiew & Straus 2006, p. 68.
^ Eu, Chiew & Straus 2006, p. 72.
^ Eu, Chiew & Straus 2006, p. 76.
^ Eu, Chiew & Straus 2006, p. 80.
^ Eu, Chiew & Straus 2006, p. 92.
^ Eu, Chiew & Straus 2006, p. 98.
^ Eu, Chiew & Straus 2006, p. 114.
^ Eu, Chiew & Straus 2006, p. 116.
^ Eu, Chiew & Straus 2006, p. 128.
^ Eu, Chiew & Straus 2006, p. 134.
^ Eu, Chiew & Straus 2006, p. 144.
^ Eu, Chiew & Straus 2006, p. 124.
^ Eu, Chiew & Straus 2006, p. 90.
^ Eu, Chiew & Straus 2006, p. 126.
^ Eu, Chiew & Straus 2006, p. 42.
^ 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.{{cite report}}: CS1 maint: others (link)
"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.