Ink

I am not an ink expert but I know enough to suggest that you want to consider defining the application so those that do know about ink can make accurate suggestions/recommendations instead of just tossing out a long list of inks on the market.

Find out what the makers of the pens used to write onto Cd's used it is water based.

Yes more details on your needs, application and specifications keep them generic if need be.

But also keep in mind ink in general and pen or writing instrument inks water based or otherwise may not be necessarily evironmentally safe. e.g. the surface tension of water is ~70 dyne. Plastics such as those used for making a CD are generally lower ~28 - 30 dyne. Something in the ink chemistry has to drop waters surface tension to get it to smoothly wet the plastic. And those are just the addtives, the main ingredients carrier, colorant, binder etc. could be more qustionable. It is a tough but not always an insurmountable problem for the ink maker.

We use an ink for stamping aluminium heat exchanger cores if this is applicable to your application (i.e Al) I can dig out the datasheet for its composition.