Gilsonite in Flexographic and Gravure Inks
Solvent-based flexo and gravure inks for packaging sometimes use gilsonite in black shades.
Benefits
- Deep black at low cost
- Good adhesion to paper and board
- Solubility in aromatic and aliphatic solvents
Limitations
- Not suitable for food-contact inks without proper approval
- Dark colour limits use to black inks
Formulation tips
Dissolve gilsonite in the solvent blend first, then add pigment and other resins.
Solvent systems
Flexo and gravure inks dry by evaporation, so the resin must dissolve in fast solvents. Gilsonite dissolves in aromatic and some aliphatic solvents but not in alcohols, which limits use in alcohol-based flexo inks.
Where it fits
- Black solvent gravure inks for paper and board
- Industrial marking and coding inks
- Specialty packaging inks where food contact is not a concern
Formulation tips
| Step | Tip |
|---|---|
| Dissolve | Gilsonite in aromatic solvent first |
| Combine | With compatible resins |
| Pigment | Add carbon black and mill |
See ink grade gilsonite and micronized gilsonite.
Recommended product
Ink & Paint Grade Gilsonite
| Property | Typical value | Test method |
|---|---|---|
| Appearance | Dark brown–black powder | Visual |
| Softening point (R&B) | 150 – 180 °C | ASTM D36 |
| Ash content, max | 3 % | ASTM D3174 |
| Moisture, max | 1 % | ASTM D95 |
| Solubility in toluene, min | 99 % | ASTM D2042 |
| Particle size | 200 – 600 mesh | Sieve |
| Typical dosage | Ink varnish: 20–40 % in oil | |
| Packing | 25 kg paper bags with PE liner, palletized. | |
Typical values. The final specification is confirmed in the COA of each shipment.
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