The Chemistry Behind Banknotes – Paper And Polymer

Chemistry Behind Bank notes

UK plans to replace all of its banknotes that were made with paper with polymer notes, leaving out the fifty pound note. Australia has been using these types of notes for more than 25 years now, so there must be some benefits to it. The Reserve Bank of India after discussion with the Indian Government has also tried to introduce plastic substrate notes of 10 rupees denomination. In this post we will discuss the chemistry and the benefits of using different materials in the currency.

The paper notes we use are also not made out of wood pulp but a sort of cotton paper mixed with other textiles in minute quantities. Bi axially oriented polypropylene used to make the polymer notes we were discussing before. The term refers to the process where it is stretched in the opposite directions during fabrication. The films transparency and strength are amplified by this stretching process.

The Indian currency we use is a solid 80-90 gms per square meter starch paper that has been mixed with various different textile fibers. The precise ingredients that go into making the cloth-ish paper we are discussing here is confidential and so is the formula for the ink it’s being printed with. The paper and ink together create a specific texture that contributes to the feel of the note.

The question most of you would have is, Why the switch from paper currencies to these new materials?

Firstly, these polymer notes have a high durability around 2.5 times more than the previous paper versions. The durability directly affects the cost that goes into making these notes. Due to their composition these new notes do not get dirty fast, they are waterproof and difficult to tear. The production cost is slightly more than the usual notes but it is a fair deal as them being plastic, they are easily recyclable. The paper notes we now use need to be shredded and burned.

Secondly, counterfeiting polymer notes is harder than their paper counterparts. The complexity of producing them gives them an edge over the paper notes. The security features present are difficult to recreate on plastic. We’ll discuss the various features being implemented throughout the world. The most common are Optically Variable Devices (OVD’s) which work on the concept that when external factors change (viewing angle or the light) the colors changes. Another one of the security features is impregnating sections of the note with compounds that change color when viewed under ultraviolet light.

Of course this article just skims through the basic information one needs to know about notes and the chemistry involved in manufacturing them. Many countries as discussed above have started making use of the polymer notes and more are believed to get on board with the idea in the future.

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