ACURE™ AQ Resins for Waterborne Coatings –A Formulator's Guide
Fast curing waterborne 2K without popping
For formulators of industrial coatings, finding the ideal resins for waterborne coatings requires balancing performance, safety, and application efficiency. With ACURE™ AQ, we’re introducing a waterborne version of our revolutionary 2k waterborne technology designed to eliminate these compromises. This platform offers significant advantages like faster cure, long pot-life, and an improved product safety profile in comparison to conventional waterborne 2K PU systems.
The key distinguishing feature is that this system does not suffer from reactive blistering, or so-called popping, which offers a massive gain in quality of finish as applicators no longer have to worry about film thickness limitations. This guide provides a comprehensive overview of the technology, performance data, and formulation best practices.
Michael Addition: The Curing Mechanism
The unique capabilities of ACURE™ AQ stem from its advanced curing mechanism. Unlike traditional isocyanate-based waterborne resins, this system is built on Michael Addition chemistry. This reaction is powered by a proprietary blocked catalyst that remains inert in the can but activates upon application, enabling both a remarkably long pot-life and an exceptionally fast cure.
Crucially, this non-isocyanate chemistry has no side reactions with water, preventing the formation of CO2 gas—the root cause of popping defects that plague standard 2K PU systems.
Catalyst becomes deblocked by the release of CO2 creating the strong base needed in the Michael addition reaction
Strong base catalyst deprotonates the donor-site, which enables reaction with the acceptor double bond. Resulting in carbon-carbon crosslinking
Extremely fast cure/conversion once catalyst is de-blocked
No side reactions with water, no toxic metal catalyst
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Cure Kinetics & Hardness Development
The efficiency of our waterborne coating resins is evident in the cure kinetics. Even at ambient room temperature, the system achieves a high crosslink density, with nearly 70% double bond conversion after just one day.
Crosslink Density & Final Hardness
Forced curing accelerates the process significantly, achieving nearly 100% conversion and a higher final crosslink density.
Double bond conversion, FTIR, 810 cm-1
A high x-linking density is already feasible with pure room temperature cure. Full conversion is achieved by forced cure.
This directly translates to improved hardness and resistance properties, with the glass transition temperature (Tg) increasing from 82.5°C at room temperature to 92.9°C when cured at 80°C for one hour. This demonstrates the versatility of the resin to meet different production demands.
Hardness Development Over Time
ACURE™ AQ has a clear advantage during the initial stages of cure, enabling faster cycle times for end-users.
While the final hardness of a typical waterborne 2K PU may eventually be higher, ACURE™ AQ's rapid early development allows for parts to be handled and moved far sooner, optimizing workflow and factory space.
Hardness development 23 °C / 50 % RH
Application Performance: Solving Formulation Headaches
This advanced 2k waterborne technology was specifically designed to overcome the most common frustrations faced by applicators and formulators.
Outstanding Pot-Life: Usability Beyond 28 Days
One of the most significant breakthroughs offered by these resins for waterborne coatings is the outstanding pot-life. Because the catalyst remains blocked in a sealed container, formulations show almost no loss in performance over time.
König Hardness of Stored Paint
Our testing shows that even after 28 days of pot-life, the mixed paint retains:
- Over 80% of its initial hardness
- Excellent chemical resistance (>200 MEK double rubs)
- No loss of gloss performance.
This unique stability drastically reduces paint waste and eliminates inconsistent quality, a common issue with short-pot-life 2K PUs.
Complete Elimination of Popping Defects
The core value of this non-isocyanate 2k paint technology is its immunity to reactive blistering. As shown in our gradient film thickness tests from 80 to 120 microns, the finish is flawless. The maximum coating thickness is now determined by the coating's sag performance, not by a chemical popping limit, offering unprecedented application latitude.
Rapid Early Water Resistance
Coatings formulated with ACURE™ AQ can be handled and even exposed to the elements much sooner than conventional systems.
A water spot test conducted just 2 hours after application showed that while the reference 2K PU suffered irreversible damage, the ACURE™ AQ topcoat swelled but fully regenerated with no visible marks, even after 24 hours of water exposure.
| Exposure time | ACURE™ AQ Topcoat | wb 2k PU Topcoat |
|---|---|---|
| 1 h | ok | soft/sticky |
| 3 h | small blisters/regen. | whitish/flat |
| 5 h | small blisters/regen. | whitish/flat |
| 7 h | small blisters/regen. | whitish/flat |
| 24 h | small blisters/regen. | whitish/flat |
System Durability and Compatibility
A topcoat is only as good as the system it's a part of. We have conducted extensive testing to ensure robust performance and compatibility.
Weathering & UV Durability
Xenon weathering tests show good gloss retention, meeting demanding industry specifications such as the German Railway Standard (>50 GU at 20° after 1500h). This confirms the suitability of ACURE™ AQ for durable topcoats in transport and industrial applications.
System Adhesion and Flexibility Over Epoxy Primers
ACURE™ AQ demonstrates excellent adhesion to our water-based epoxy primers, such as the BECKOPOX™/BECKOCURE™ systems. Our tests show that with a flexible primer, the entire coating system achieves outstanding impact resistance (>50 inch-pounds) and flexibility (0mm Conical Mandrel). This proves the topcoat maintains system integrity without becoming a weak point. Excellent intercoat adhesion is achieved even with short recoat windows of 2-6 hours, enabling higher throughput.
| Impact (ASTM D-2794), inch-pounds |
Erichsen indentation (DIN 53156), mm |
Conical Mandrel (DIN 6860), mm |
Adhesion (DIN 53151), Gt |
||
|---|---|---|---|---|---|
| face | reverse | ||||
| Primer (EP 2387/EH 2100) | 60 | 10 | 7.7 | 0 | n.a. |
| Primer + ACURE AQ Topcoat red | 70 | 30 | 9.6 | 0 | 0-1 |
| Primer + ACURE AQ Topcoat yellow | 80 | 50 | > 10 | 0 | 0-1 |
| Primer + wb 2k Topcoat yellow | 70 | 30 | > 10 | 0 | 0-1 |
| Impact (ASTM D-2794), inch-pounds |
Erichsen indentation (DIN 53156), mm |
Conical Mandrel (DIN 6860), mm |
Adhesion (DIN 53151), Gt |
||
|---|---|---|---|---|---|
| face | reverse | ||||
| Primer (EP 2384/EH 2261) | 20 | <5 | 1.0 | 11 cm | n.a. |
| Primer + ACURE AQ Topcoat red | 20 | <5 | 5.9 | 0 | 0-1 |
| Primer + ACURE AQ Topcoat yellow | 20 | <5 | 8.7 | 0 | 0-1 |
| Primer + wb 2k Topcoat yellow | 20 | <5 | 9.9 | 0 | 0-1 |
| > 200 MEK double rubs! | |||||
| BECKOPOX® EP 2387w/53WA BECKOCURE® EH 2100w/44WA |
Cross cut adhesion after 14 days | |||
|---|---|---|---|---|
| 2 hours | 6 hours | 24 hours | 24 h RT + 24 h 80 °C | |
| Dry Time Primer | ||||
| ACURE AQ yellow | 0-1 | 0-1 | 0-1 | 0 |
| wb 2K PU yellow | 0 | 0 | 0-1 | 0 |
| BECKOPOX EP 2384w/57WA BECKOCURE EH 2261w/41WA |
Cross cut adhesion after 14 days | ||||
|---|---|---|---|---|---|
| 2 hours | 6 hours | 24 hours | 24 h RT + 24 h 80 °C | 24 h RT + 24 h 80 °C + sanding | |
| Dry time Primer | |||||
| ACURE AQ yellow | 1-2 | 1 | 1 | 5 | 0-1 |
| wb 2K PU yellow | 1 | 1 | 1 | 1 | 1 |
It is advisable to sand force cured/baked epoxy primer, if compatibility has not been tested upfront. With our newly developed ultra-low VOC flexible primer system, sanding can be avoided while also keeping total VOC emissions at the lowest possible level.
Fast primers based on EP 2384 and EH 2261 can be overcoated after short ambient cure.
System Adhesion and Flexibility Over Epoxy Primers
Our deep-dive testing revealed a critical insight for formulators creating a non-isocyanate 2k paint system. The choice of filler in the epoxy primer can dramatically impact corrosion resistance when overcoated with ACURE™ AQ. Primers formulated with talc showed strong delamination after 168 hours of salt spray. By replacing talc with an alternative filler like Silitin Z 89, this issue was completely resolved. This expert guidance is crucial for ensuring optimal system performance.
| Part | Components |
|---|---|
| I |
Deion. Water ADDITOL VXW 6208 ADDITOL VXW 6393 |
| II |
Talcum
Kronos 2190Bayferrox 3920 Bayferrox 306 EWO |
| III |
ADDITOL VXW 6393 Texanol |
| IV |
ADDITOL VXW 6388 Methoxypropanol |
| Slurry | |
| V | BECKOPOX EP 2384w/57WA |
| VI | BECKOPOX EH 2261w/41WA |
Salt spray test after 168 hours
Untreated steel panels (Gardobond OC)
Drying primer 24 h before topcoat application
DFT: 50-60 µm / 40-50 µm (Primer / Topcoat)
| Part | Components |
|---|---|
| I |
Deion. Water ADDITOL VXW 6208 ADDITOL VXW 6393 |
| II |
Sikitin Z 89 or Aktisil AM
Kronos 2190Bayferrox 3920 Bayferrox 306 EWO |
| III |
ADDITOL VXW 6393 Texanol |
| IV |
ADDITOL VXW 6388 Methoxypropanol |
| Slurry | |
| V | BECKOPOX EP 2384w/57WA |
| VI | BECKOPOX EH 2261w/41WA |
Salt spray test after 168 hours
Untreated steel panels (Gardobond OC)
Drying primer 24 h before topcoat application
DFT: 50-60 µm / 40-50 µm (Primer / Topcoat)
New Standard for Waterborne Coating Resins
The comprehensive data shows that the ACURE™ AQ platform sets a new performance standard. By eliminating the inherent chemical flaws of traditional 2K PU systems, these resins for waterborne coatings empower formulators to create safer, more efficient, and more reliable products without compromise.
ACURE™ AQ 620-100
Description: Water borne, Fast curing, no risk for popping, highly flexible and good outdoor durability
Function: The ACURE™ AQ binder
Technology: Non ionically stabilized WB PUD
Key parameters: 42% in water
Ready to see how this revolutionary 2k waterborne technology can transform your formulations?
Contact our technical experts below.
Product Selector for ACURE™ Coating Resins
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Oliver Truchses
Expert for ACURE™ Coating Resins
