Unbelievably break-resistant – coloured pencils with protective lead coating

Exploiting nature’s secrets

What do insects and the new Noris Club triplus coloured pencils have in common?

Well, both can appear in various colours, but otherwise they look completely different. What really makes the insect unique is the way it has been developing and optimising its evolutionary state for over 400 million years. Insects have the greatest species variety of any life form on this planet; they’re the toughest life form too, and have every potential to outlive us human beings. So what could be more obvious than to take a closer look at this life form, to learn from it and its structure, to take a few positive ideas from the way it is made, and put them in a pencil?

And now we can answer the question we asked at the beginning about what they have in common – answer: their mechanical structure.

While mammals support their shape by means of an internal skeleton, thus giving their internal organs only limited protection against outside forces, insects rely on an outer skeleton, in the form of a hard shell, the so-called chitin shield, which surrounds their vulnerable insides protectively like a casing. It is exactly this principle which we have now imitated for the new generation of coloured leads in the Noris Club triplus.

While a normal coloured lead supports itself only through its inner “skeleton” – its bond of cellulose derivates – our new leads also have a neutral, more rigid protective casing, analogous to an insect’s chitin shield. It can be recognised by a white ring round the coloured lead – the so-called lead casing.

But what does a casing do when you are using it?

As the following sketch shows, when a lead is subject to external forces, the body of the lead undergoes various stresses. While in the compressed upper side this causes relatively harmless compression stresses, on the opposite side, i.e. in the side drawn, you will find dangerous tensile stresses. Once these exceed the integrity of the lead, they will inevitably cause the lead itself to break. But it is exactly here that the lead casing proves its worth, providing considerably better cushioning against the high stress on the edges (long arrow in the sketch) due to its increased rigidity, and thus preventing premature breakage to the lead as a whole. This is effective e.g. when the pencil is pressed very heavily against the paper, as children do when they are drawing, and in sharpening, for this is when the pencil and its lead must withstand the greatest pressures.

Research has shown that using a casing increases the stability of the pencil lead by more than 20%, thus offering the user easy writing and sharpening, just like high-quality pencils. By lessening breakage to the lead the overall performance of the pencil is extended, and painting and drawing can continue without let or hindrance.