Guardian (polymer)
Guardian is the trademark name of a polymer manufactured by Innovia Films Ltd. 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.[1] 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.[1][2][3] This consists of a 37.5µm thick polypropylene sheet sandwiched between two 0.1 µm polyolefin sheets,[3][2] 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.[1] The cast tube material is then reheated and blown into a large bubble using air pressure and temperature.[1] 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.[3][1] This creates the base biaxially-oriented polypropylene substrate of 75.4 µm thickness, called ClarityC by Innovia Films.[2][4]
The base substrate is slit as it exits the convergence rollers.[1][3] Four 3 µm thick layers of (usually white) opacifier are applied to the substrate, two on the upper surface and two on the lower surface.[2][3] A mask prevents the deposition of the opacifier on parts of the substrate that are intended to remain transparent.[5] These overcoat layers protect the substrate from soiling and impart on it its characteristic texture,[6] and increase the overall thickness to 87.5 µm. The resulting product is the Guardian substrate.[3]
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.[4] The resulting polymer substrate then passes through a rotary printing press using chrome-plated copper cylinders.[4] After printing, the holographic security foil is incorporated into the base substrate.[4] This is then cut into sheets and transported to the banknote printing companies in wooden boxes as a secure shipment.[4][7]
Properties
Guardian is a non-porous and non-fibrous substrate.[1] Because of this, it is "impervious to water and other liquids", and so remains clean for longer than a paper substrate.[1] It is difficult to initiate a tear on the substrate, which has higher tear initiation resistance than paper.[1]
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:
In 1993, the Bank of Indonesia issued a commemorative Rp 50,000 banknote and the Central Bank of Kuwait issued a د.ك1 banknote.[13] In 1998, the Bank Negara Malaysia issued a commemorative RM50 banknote,[13] and the Central Bank of Sri Lanka issued a commemorative Rs200 banknote.[26] In 1999, the Northern Bank of Northern Ireland issued a commemorative GB£5 banknote,[27] and the Central Bank of the Republic of China in Taiwan issued a commemorative NT$50 banknote.[28][13] In 2000, the Central Bank of Brazil issued a commemorative R$10 banknote[29] and the People's Bank of China issued a commemorative ¥100 banknote.[13] In 2001, the Central Bank of Solomon Islands issued a commemorative SI$2 banknote.[30] In 2009, the Bank of Mexico issued a commemorative $100 banknote.[13]
Notes
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Garoffolo & Sientek 2009, p. 25.
- ↑ 2.0 2.1 2.2 2.3 Hardwick & Ghioghiu 2004, p. 6.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Innovia Security 2013.
- ↑ 4.0 4.1 4.2 4.3 4.4 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.
- ↑ 13.0 13.1 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 13.10 13.11 13.12 13.13 13.14 13.15 13.16 Innovia Security September 2013.
- ↑ 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.
- 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 (Cash and Issue Department, Bank of Spain) 3 (5): 25. Retrieved 9 March 2014.
- Hardwick, Bruee; Ghioghiu, Ana (2004). "Guardian substrate as an optical medium for security devices" (PDF). Note Printing Australia. 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. Retrieved 8 March 2014.
- "Guardian substrate issuers" (PDF). Innovia Security. September 2013. Retrieved 9 March 2014.
Further reading
- Guarner, Enrique (April 2009). "Polymer and the printing process" (PDF). Billetaria (Cash and Issue Department, Bank of Spain) 3 (5): 26–27. Retrieved 9 March 2014.