| PATENT CLAIMS |
A marking instrument comprising a marking tip & marking fluid, the fluid being applied to surface when tip is placed in contact with surface, the instrument having an improved cap-off life wherein the fluid comprises
- Volatile solvent
- Waxy additive dissolved in solvent (0.05-25%) & at level which is at least 20% of amount required to form saturated soln at 20C, said additive having melting point > 40C & capable of forming continuous solid skin over surface of marking fluid if a quantity of fluid is held in an open vessel which permits solvent evaporation from surface thereof, the additive being selected from PEG waxes etc
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