UV release coating additives should be selected by chemistry, release test and downstream print/recoat requirements. The CHLUMIAG® 2750 family is the only first route here with a public reactive-acrylic and UV reverse-varnish claim, plus 0.1–3% guidance. CHLUMIAG® 3501 is a conditional nonreactive comparison because no public dose is available.
CHLUMIAG® 3565 is removed from the first shortlist. Its detailed release claim concerns dry-process PU leather and release-paper reuse, not UV ink or overprint-varnish release; its page also publishes conflicting dosage statements and a pinhole warning.
UV release-coating decision map
| Application evidence | First route | Approval gate |
|---|---|---|
| Solvent-free or solvent-containing UV reverse varnish needs controlled release | 2750 | Cure, release force, rub and overprint/recoat |
| Broad release or anti-sticking screen is desired but dose is missing | 3501 after current TDS | Establish dose and quantified endpoint before trial |
| Project is PU-leather slurry on reusable release paper | 3565 may belong to a different project | Do not transfer the result to UV varnish |
| High release appears only when UV cure is incomplete | Correct cure first | No additive approval |
| Produk | Published facts | Supported route | Boundary |
|---|---|---|---|
| 2750 family | Reactive acrylic groups; 100% active; 0.1–3%; UV/solvent, not water | 2750 is listed for reverse varnish; 2780 for anti-blocking/anti-graffiti | Family page does not replace variant-specific cure and performance data |
| 3501 | 100% active modified polysiloxane; water/UV/solvent; any-stage addition | Broad printing, overprint-varnish and release-coating category | No public recommended dosage or quantified release result |
| 3565 | 100% active; water/UV/solvent; pinhole warning | PU-leather anti-sticking/peeling and release-paper reuse | Two public dosage statements; not a documented UV reverse-varnish route |
Define what “release” means
Release may mean pressure-sensitive tape or label release, reduced blocking between printed faces, easy separation from a process liner, or a reverse-varnish effect. These are different contact pairs and force histories. Name the adhesive, liner/film, coated side, pressure, dwell, temperature, peel angle and speed.
Also define what must remain printable, laminateable or recoatable. Very low surface energy can improve release while damaging the next operation.
Use 2750 for the documented UV reverse-varnish route
The family page states that reactive acrylic functional groups crosslink into the polymer network and lists solvent-free UV, solvent-containing UV and acrylic systems. It specifically says 2750 is more suitable for reverse varnishes. Start with a blank and compact ladder within 0.1–3%.
Confirm the photoinitiator, lamp spectrum/intensity, line speed, oxygen exposure and film weight. Test cure at the low and high ends of the production window; an under-cured surface can appear unusually releasable, tacky or weak.
Use 3501 only after dosage confirmation
3501 lists overprint varnishes and release coatings for anti-sticking, but the page provides no recommended level. It also gives no reactive-functional, release-force, rub or block data. Request the current TDS and a product-specific technical rationale before adding it.
Keep 3565 in its documented application
3565’s main release evidence is for PU leather slurry and repeated use of textured release paper. The page lists both 0.05–1% and 0.02–3%, instructs addition before curing agent and warns of pinholes. Those facts do not justify a first UV-OPV recommendation.
Measure cure, release and rub separately
ASTM D3330/D3330M includes pressure-sensitive tape peel methods and a release-liner method, but it does not automatically fit every reverse-varnish application. Agree on tape, substrate, conditioning, peel rate and acceptance criteria.
ASTM D5264 provides a laboratory rub comparison for printed materials. Pair release force with cure, surface energy/contact angle, gloss/haze, blocking, adhesion, rub, scratch and downstream overprint, lamination or recoat.
Build a production-relevant trial
- Hold resin, monomers, photoinitiator, pigments and film weight.
- Prepare a blank and one product ladder at equal active addition reporting.
- Cure across the production energy and line-speed window.
- Condition specimens before release and rub measurement.
- Repeat after warm storage and after the longest downstream-conversion delay.
Common release-coating errors
Using slip as a release-force substitute
Low friction between films is not the same measurement as peeling an adhesive or separating a coated contact pair. Define the actual interface.
Ranking under-cured UV films
Residual monomer and incomplete network formation can change tack, rub and peel. Confirm the cure window before comparing additive levels.
Transferring a family claim to every variant
The shared 2750/2760/2780/2505 page gives different application emphasis and viscosities. Request variant-specific data rather than assuming interchangeability.
Using one peel result
Release force can vary with peel rate, dwell, temperature, adhesive lot and aging. Build a matrix that represents storage and end use.
Retain the tested contact materials and record which surface fails. Adhesive transfer, cohesive failure, coating pick-off and clean release can produce similar force numbers but imply very different formulation decisions. Photograph the interface and preserve specimens for comparison after aging.
Request a release-test match
Send UV resin/monomer/photoinitiator, substrate or liner, adhesive/contact material, application and cure conditions, target release method/force, film weight, current additives, rub/block and overprint/lamination/recoat requirements. Ask Longchang Chemical for a 2750-led UV release trial and current 3501 data.