Anti-blocking additives for coatings and inks are selected to reduce unwanted adhesion when two coated or printed surfaces remain in contact under pressure, heat, or storage time. Start by confirming that the failure is true blocking—not incomplete cure, retained solvent or water, excessive film tack, or simply high sliding friction. Then screen the additive in the actual binder, cure schedule, film weight, contact pressure, temperature, and dwell time used in production.
This guide compares four Longchang routes for water-based, solvent-based, and UV-curable systems. The product recommendations are screening starting points, not a substitute for compatibility, regulatory, or production validation.
Blocking, slip, and cure are different problems
Blocking is surface-to-surface adhesion after contact. Slip describes the force required for one surface to move across another. A film can slide easily yet still block after a warm stack test; it can also show a low blocking tendency but still have excessive friction on a converting line.
Before changing the formulation, check whether the film has reached its intended conversion. For a waterborne coating, record residual water and drying conditions. For a solventborne system, confirm solvent release. For a UV system, confirm that lamp output, line speed, film thickness, pigment loading, and oxygen inhibition are not leaving an under-cured surface. An additive cannot reliably compensate for an incomplete film.
| Observed failure | First diagnostic | Primary formulation route |
|---|---|---|
| Faces adhere after stacking or rewinding | Conditioned block test | Aditif anti-blokir |
| High drag during transport or converting | Static and dynamic friction | Aditif pelumas |
| Tacky surface immediately after cure | Drying or cure verification | Process and binder correction first |
| Craters or incomplete substrate coverage | Wetting and surface-tension check | Aditif pembasah |
Which Longchang anti-blocking route should you screen?
| Produk | Best first-screen situation | Supplier starting range | Titik pengawasan penting |
|---|---|---|---|
| CHLUMIFE® 3482 / 3482X | Water-based coating or ink where anti-sticking and friction reduction are the main needs | 0.05–1% on total formulation | Water-based only; pre-dilution is required; check pinholes and freeze protection |
| CHLUMIFE® 3166 | Dry feel, smoothness, scratch resistance, and anti-blocking must be balanced across a wider system range | 0.05–1% | Check pinholes, whitening, and foam stabilization |
| CHLUMILE® 3032 | A reactive, more durable surface route is needed in an oil-based, solvent, or UV system | 0.01–1% | Confirm functional-group compatibility and avoid uncontrolled additive combinations |
| CHLUMIAG® 2750 / 2760 / 2780 / 2505 | Radiation-curable or solvent/acrylic systems requiring reactive surface control; 2780 is the anti-blocking comparison point | 0.1–3% | Not listed for water-based systems; check cure, intercoat adhesion, and later converting |
Dosages above reproduce the supplier’s published starting ranges. The lowest effective level is normally the best place to begin because excess surface-active material can create pinholes, intercoat-adhesion loss, foam stabilization, migration, or printability problems.
A practical anti-blocking trial plan
1. Freeze the control formulation
Use one production-representative control with the same resin lot, pigment or filler level, solvent or water balance, film weight, substrate treatment, and cure schedule. Do not change the additive and the drying process in the same comparison.
2. Test a compact dosage ladder
Prepare a blank plus three dosage levels around the supplier’s suggested range. Record whether the additive was pre-diluted, the dilution medium, addition stage, mixing energy, and time between preparation and application.
3. Condition samples before contact
Evaluate both early handling and fully conditioned film. State the contact face, load, temperature, humidity, dwell time, and separation method. ASTM D3354 explains why pressure and temperature can change blocking and provides a quantitative film-to-film separation method. For plastic film and sheeting, ISO 8295 is a separate method for starting and sliding friction; it should not be used as a substitute for a block test.
4. Measure the properties an improvement could damage
A release improvement is not a pass if the film loses adhesion, gloss, recoatability, printability, sealing performance, or lamination bond. At minimum, compare:
- blocking force or an agreed visual rating after controlled conditioning;
- static and dynamic friction where web transport matters;
- gloss, haze, leveling, and pinholes;
- crosshatch or another agreed adhesion method;
- rub, scratch, and abrasion resistance after full cure;
- recoat, overprint, lamination, tape, or heat-seal performance relevant to the end use.
How to interpret common trial failures
Blocking improves, but pinholes appear
Reduce dosage, revisit dilution and addition order, and check whether surface-tension reduction is too aggressive. This watchpoint is specifically disclosed for CHLUMIFE® 3482/3482X and 3166.
The film feels dry but still blocks in warm stacks
Do not use hand feel as the release test. Re-check conversion, conditioned contact time, pressure, and temperature. A dry surface can still develop adhesion during storage.
Blocking improves, but the next layer loses adhesion
Surface enrichment may be interfering with recoating, printing, lamination, or tape bonding. Move down the dosage ladder or compare a route positioned for reactive or durable incorporation. ASTM D3359 is a useful reference for rating coating adhesion to metallic substrates, but the method, film thickness, operator technique, and substrate must be agreed before comparing results.
What information should accompany a sample request?
Send the binder chemistry, water/solvent/UV system, pigment or filler content, substrate and treatment, wet and dry film weight, cure conditions, current additive package, contact-face combination, stack or reel pressure, temperature, dwell time, and the required downstream operations. Include both the present blocking result and the acceptance target. This information is more useful than asking for a generic “non-stick additive.”
Frequently asked questions
Should I choose 3482 or 3482X?
Both are water-based microemulsion routes. The supplier states that 3482X contains a thickener and offers better dilution stability. Compare them in the actual let-down water, viscosity window, and storage time used in your plant.
Is a lower coefficient of friction proof of anti-blocking?
No. Friction and blocking are related surface properties but answer different questions. Report a conditioned contact test and a friction test separately.
Can these products be used in food-contact packaging?
This article does not establish food-contact suitability or regulatory compliance. Compliance depends on the complete formulation, printed structure, migration or set-off risk, use conditions, and target jurisdiction. Request current regulatory documentation and validate the finished article with the responsible converter or compliance specialist.
Request a focused anti-blocking comparison
For a useful first recommendation, send the system, substrate, cure schedule, contact conditions, current result, and properties that must not change. Ask Longchang Chemical for an anti-blocking sample shortlist and include your target test method in the message.