Английская Википедия:Guardian (polymer)
Guardian is the trademark name of a polymer originally manufactured by Securency International,Шаблон:Sfn 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.Шаблон:Sfn 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.Шаблон:SfnШаблон:SfnШаблон:Sfn This consists of a 37.5µm thick polypropylene sheet sandwiched between two 0.1 µm polyolefin sheets,Шаблон:SfnШаблон:Sfn 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.Шаблон:Sfn The cast tube material is then reheated and blown into a large bubble using air pressure and temperature.Шаблон:Sfn 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.Шаблон:SfnШаблон:Sfn This creates the base biaxially-oriented polypropylene substrate of 75.4 µm thickness, called ClarityC by Innovia Films.Шаблон:SfnШаблон:Sfn
The base substrate is slit as it exits the convergence rollers.Шаблон:SfnШаблон:Sfn Four Шаблон:Convert thick layers of (usually white) opacifier are applied to the substrate, two on the upper surface and two on the lower surface.Шаблон:SfnШаблон:Sfn A mask prevents the deposition of the opacifier on parts of the substrate that are intended to remain transparent.Шаблон:Sfn These overcoat layers protect the substrate from soiling and impart on it its characteristic texture,Шаблон:Sfn and increase the overall thickness to 87.5 µm. The resulting product is the Guardian substrate.Шаблон:Sfn
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.Шаблон:Sfn The resulting polymer substrate then passes through a rotary printing press using chrome-plated copper cylinders.Шаблон:Sfn After printing, the holographic security foil is incorporated into the base substrate.Шаблон:Sfn This is then cut into sheets and transported to the banknote printing companies in wooden boxes as a secure shipment.Шаблон:SfnШаблон:Sfn
Properties
Guardian is a non-porous and non-fibrous substrate.Шаблон:Sfn Because of this, it is "impervious to water and other liquids", and so remains clean for longer than a paper substrate.Шаблон:Sfn It is difficult to initiate a tear on the substrate, which has higher tear initiation resistance than paper.Шаблон:Sfn
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 Шаблон:Currency banknote and the Central Bank of Kuwait issued a د.ك1 banknote.Шаблон:Sfn In 1998, the Bank Negara Malaysia issued a commemorative Шаблон:Currency banknote,Шаблон:Sfn and the Central Bank of Sri Lanka issued a commemorative Rs200 banknote.Шаблон:Sfn In 1999, the Northern Bank of Northern Ireland issued a commemorative Шаблон:Currency banknote,Шаблон:Sfn and the Central Bank of the Republic of China in Taiwan issued a commemorative Шаблон:Currency banknote.Шаблон:SfnШаблон:Sfn In 2000, the Central Bank of Brazil issued a commemorative Шаблон:Currency banknoteШаблон:Sfn and the People's Bank of China issued a commemorative ¥100 banknote.Шаблон:Sfn In 2001, the Central Bank of Solomon Islands issued a commemorative SI$2 banknote.Шаблон:Sfn In 2009, the Bank of Mexico issued a commemorative $100 banknote.Шаблон:Sfn
Notes
References
- Шаблон:Cite news
- Шаблон:Citation
- Шаблон:Cite book
- Шаблон:Cite journal
- Шаблон:Cite web
- Шаблон:Cite news
- Шаблон:Cite report
- Шаблон:Cite web
- Шаблон:Cite web
Further reading
