Why Do Some Promotional Pens and Promotional Highlighters Dry Out Quicker Than Others?

I've only just bought that promotional pen and it haswhen analysing the reasons some personalised pens
run out already, I hear you say. Well we have alldry out quicker than others and that is because
experienced that at some time and discounting thecases can be made from different materials. Some
fact that the odd one here and there is faulty thereare porous and allow the solvents to evaporate
are good technical reasons why some customisedthrough them even when the cap is in position. As a
pens last longer than others.general rule plastic pens or highlighters made from
Firstly, not all inks are equal. Ballpoint pens use a veryStyrene, PVC or ABS will not last as long as metal
thick oily solvent which does not evaporate quicklypens or pens made from polypropylene because
even with the cap off so they are less prone tothese materials are not porous and consequently the
drying out. Not only that but the pigment to solventsolvents cannot migrate through their walls.
ratio is high so it needs less ink deposits to achieveSo, why are promotional pens, markers and
strong blacks or blues and hence less is used.highlighters not always made from metal or
Rollerballs on the other hand require solvents that arepolypropylene because surely it would solve this
very thin so they can flow more easily and theseproblem of drying out? There are two primary
tend to evaporate very quickly. Hence, a cap isreasons why they are not always made from metal
normally required on a rollerball to prevent the solventor polypropylene and these are either price or
drying out. The pigment to solvent ratio is also lowerdifficulties in printing the barrels when used as a
in a rollerball so a larger amount of wet ink is actuallybusiness gift or a promotional item. Polypropylene has
deposited when writing to achieve the same densityto be flamed to reduce the surface tension before it
of colour as a ballpoint pen. This problems also seencan be printed and this is dangerous and costly. If the
with promotional markers and promotional highlighterscases are made from metal they are expensive so
where very volatile solvents have to be used to aidas price is king in the promotional pen market some
fast drying when used for writing or marking.manufacturers choose to use normal plastic materials
There is one other very important considerationwhich gives them a price advantage.