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Home / News / Industry News / UV Coating Poor Leveling and Tape Adhesion — How to Improve Surface Performance?
Industry News
UV Coatings · UV Varnish · Photo-Curable Systems · DH-4270
In UV varnish, UV coatings, and other photo-curable systems, the film can complete curing after ultraviolet irradiation, providing advantages of fast cure speed and high production efficiency. But faster curing also means the film surface state must stabilise in a shorter time window. If the coating does not wet and flow sufficiently during application and curing, surface texture problems and insufficient surface lubricity can result. Additionally, for products requiring tape testing, lamination, or subsequent processing, the film surface's anti-tack capability is equally important.
UV Film Surface Lubricity Insufficient
After curing, the film surface has relatively high friction resistance — hand feel and surface touch are not ideal, and subsequent processing may be affected.
Tape Test Shows Adhesion
Some UV coatings develop strong adhesion after contact with tape — especially noticeable in applications where surface release performance is required.
Flow and Surface Effect Difficult to Balance
If the system has insufficient flowability and curing speed is fast, some surface defects may not be fully corrected before the film is completely cured.
Additive Effect Changes Over Time
Some non-reactive surface additives primarily rely on migration to the film surface to act — as use environment and time change, surface performance may show some fluctuation.
Why UV Systems Need to Consider the "Fixation" Problem for Surface Additives
Ordinary surface additives typically act by reducing surface tension and improving the interfacial state. For UV photo-curable systems, if the additive only resides on the film surface without participating in the formation of the cured network, its long-term stability may be affected by system composition and use environment. Therefore, for UV varnishes with higher requirements for surface performance durability, surface additives with reactive groups can be considered. These additives can participate in resin network formation during curing, so they are not simply present on the film surface but form a more stable bonding relationship with the cured system.
DH-4270: Reactive Surface Additive for UV Systems
DH-4270 is a surface additive for UV reverse varnish and photo-curable systems, with reactive acrylic functional groups that can participate in polymer network structure formation during UV curing, making the additive more stably present in the cured film. In application, DH-4270 can help improve coating spread state, making the film surface more uniform, while improving the slip performance and tape release behaviour of the cured film. Compared to additives that rely purely on surface migration, its reactive structure is better suited to photo-curable systems with certain durability requirements for surface performance.
The product is mainly suitable for solventborne UV coatings, UV photo-curable systems, and some acrylic resin systems. Reference dosage: 0.05%–1.0% of total formulation.
UV varnish surface problems are not simply about whether leveling is good — slip performance, tape release, and the stability of the additive in the cured film are all worth attention. For UV systems that need to maintain surface performance long-term, selecting a reactive surface additive allows it to participate in the cured network formation, improving leveling and slip effect while reducing performance changes caused by additive migration.
Frequently Asked Questions
Why is a reactive surface additive more durable in UV systems than a non-reactive one?
Non-reactive additives rely on surface concentration — they migrate toward the film surface during curing and provide surface modification through their presence there. However, their concentration at the surface can change over time with further migration, solvent extraction, or mechanical contact. Reactive additives with acrylic functional groups co-polymerise into the network during UV cure, anchoring them at the positions where they were concentrated at the point of cure — this locked-in position is maintained through the service life rather than being subject to ongoing redistribution.
Does DH-4270 affect the cure speed or photoinitiator efficiency in UV systems?
At the recommended dosage range (0.05%–1.0%), the reactive acrylic groups in DH-4270 participate in the UV-initiated radical polymerisation alongside the base oligomers and monomers. At low addition levels, the effect on overall cure speed is minimal. At higher dosages, the effect on cure profile should be evaluated alongside the target surface performance to confirm the appropriate addition level for the specific UV system.
