SUPER ACCELERATED EXPOSURE TEST
Fast screening of TiO₂ weatherability
Super accelerated exposure testing is a durability evaluation method designed to rapidly assess the
photocatalytic durability of titanium dioxide (TiO₂) in coating systems.
Unlike conventional accelerated weathering tests, which mainly reflect resin‑driven degradation,
super accelerated exposure selectively intensifies TiO₂‑driven photocatalytic deterioration,
enabling clear differentiation of TiO₂ performance within a much shorter timeframe.
Are You Using the Right Method to Evaluate TiO₂ Durability?
As durability expectations for exterior coatings continue to increase, differences between results obtained from conventional accelerated weathering tests and
natural outdoor exposure have become more apparent.
While QUV and Xenon Weather‑Ometer (XWOM) testing remain essential industry standards,
they do not always reliably predict long‑term performance under natural exposure conditions—particularly as service life requirements extend.
Understanding what each test method can, and cannot, evaluate is therefore critical when assessing TiO₂ durability.
The correlation data shown below illustrates how results from conventional accelerated tests increasingly diverge from natural exposure as durability requirements extend.
Correlation Between QUV / XWOM and Natural Exposure
Comparison studies show that TiO₂ durability rankings obtained from QUV or XWOM frequently do not correlate well with natural outdoor exposure results.
While these tests effectively evaluate resin stability, the relative performance order of TiO₂ grades observed under QUV or XWOM conditions may differ from that seen after prolonged natural exposure.
This mismatch indicates that QUV and XWOM alone are insufficient for determining the intrinsic durability of TiO₂ within a coating system.
The durability order in QUV-A, QUV-B and XWOM is totally flipped from the result of natural exposure test.
Why TiO₂ Durability Requires a Different Evaluation Approach
TiO₂ contributes to coating degradation through photocatalytic activity. Under UV irradiation, TiO₂ generates reactive species that locally attack organic binders at the pigment–resin interface.
This mechanism is fundamentally different from uniform resin oxidation. Instead of overall vehicle shrinkage, TiO₂‑driven degradation produces localized binder loss and hole formation around pigment particles—features that are not clearly distinguished in conventional accelerated tests.
To evaluate TiO₂ durability effectively, a test method must intentionally accelerate this photocatalytic process.
Resin Deterioration by Hydrolysis& Oxidation
Resin Deterioration by Photocatalysis
Super Accelerated Exposure: Targeting TiO₂ Durability
Super accelerated exposure testing selectively accelerates TiO₂‑driven photocatalytic degradation, enabling rapid differentiation of pigment durability under controlled conditions.
By intensifying radical generation using hydrogen peroxide, the test reveals relative TiO₂ performance much faster than conventional methods—without altering the fundamental degradation mechanism—unlike QUV or XWOM, which primarily reflect resin performance.
Correlation Between Super Accelerated Exposure and Natural Exposure
Correlation data demonstrate that TiO₂ durability rankings obtained from super accelerated exposure closely align with those observed in natural outdoor exposure.
Trends in gloss retention and surface deterioration under super accelerated conditions mirror long‑term natural exposure behavior, but within a practical laboratory timeframe.
This strong correlation makes super accelerated exposure an effective screening tool for identifying durable TiO₂ grades before committing to extended weathering programs.
Understanding the Deterioration Mechanism
Effective coating durability evaluation requires multiple complementary tests, each addressing a different aspect of performance.
Recommended Evaluation Approach Durable Coating Systems
- Use XWOM and QUV to evaluate resin
- Evaluate and compare TiO₂ photocatalytic durability and confirm the durability and superiority of ISK’s super durable TIPAQUE PFC105, using ISK’s Super Accelerated Exposure Test on your samples
- Proceed to natural exposure testing to obtain total durability data for both resin and TiO₂ under real outdoor conditions
By combining conventional accelerated testing with super accelerated exposure and natural exposure,
customers can confidently develop coating systems with optimized durability and fully realize the performance benefits of
ISK’s super durable TiO₂, PFC105.
TIPAQUE® PFC105 : Super Durable TiO₂ for Long‑Life Coatings
TIPAQUE® PFC105 is ISK’s super durable titanium dioxide, engineered to suppress TiO₂‑driven photocatalytic degradation and support
long‑term appearance retention in exterior coatings.
By controlling durability at the pigment level, PFC105 enables coating designs in which titanium dioxide no longer limits service life.
Appendix
Why TiO₂ Matters
In exterior coatings, titanium dioxide plays a central role not only in opacity and color but also in long‑term durability. Under UV exposure, TiO₂ can accelerate binder degradation through photocatalytic reactions, directly impacting coating lifetime.
- Binder degradation
- Gloss & color loss
- Surface chalking
Accurate evaluation of TiO₂ weatherability is therefore critical when selecting pigments for durable coating formulations.
Photocatalytic Activity of TiO₂
TiO₂ photocatalysis occurs when UV irradiation generates electron–hole pairs within the TiO₂ lattice, leading to the formation of reactive oxygen species that attack organic binders.
Super Accelerated Exposure Test
- UV irradiation(Xenon light) activates TiO₂ photocatalysis
- Hydrogen peroxide accelerates reactive radical formation
- The fundamental degradation mechanism remains unchanged
Super accelerated exposure combines UV irradiation and hydrogen peroxide to intensify TiO₂ photocatalytic activity, accelerating degradation.
