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RIASORB® UV-571UL: A Liquid UV Absorber Designed for High-Performance and Sustainable Applications

2026-06-25


High-performance polymer materials — including TPU, coatings, EVA, PVC, and optical adhesives — are often exposed to challenging outdoor environments. Over time, manufacturers may encounter issues such as:


  • Yellowing, gloss loss, or cracking after prolonged UV exposure

  • Poor dispersion and limited loading levels associated with conventional powder UV absorbers

  • Haze or crystallization under low-temperature processing or high additive loading conditions


To address these challenges, Rianlon has developed RIASORB® UV-571UL, a liquid benzotriazole UV absorber designed to provide long-term weatherability while maintaining processing efficiency and formulation flexibility.


RIASORB® UV-571UL

Chemical Classification: 

Liquid benzotriazole UV absorber



CAS No.: 125304-04-3 / 23328-53-2


Appearance: Light yellow to yellow liquid


Key Target Matrixes: Thermoplastic polyurethane (TPU), structural coatings, specialized adhesives, PVC, PVB, PMMA, EVA, and various elastomers requiring stringent appearance retention.




Four Key Advantages



Efficient, Broad-Spectrum UV 

Protection for Enhanced Weatherability

01

PART.ONE

RIASORB® UV-571UL



Application testing indicates that RIASORB® UV-571UL provides strong and broad UV absorption across the 280–380 nm wavelength range, helping protect polymers from UV-induced degradation.

Note: The above UV–Vis absorption spectrum was recorded using a 10 mg/mL solution.


Its relatively high molar extinction coefficient also offers several formulation advantages:


1

Effective UV protection at relatively low dosage levels

2

Reduced impact on transparency and processing performance

3

Greater flexibility in formulation optimization


These characteristics are especially valuable for appearance-sensitive applications such as clear coatings, optical adhesives, PVB, and PMMA.









02

PART.TWO

Excellent Long-Term Weathering 

Performance and Color Stability

RIASORB® UV-571UL




Under SAE J2527 xenon-arc weathering testing for automotive white coatings, RIASORB® UV-571UL demonstrated excellent long-term aging performance.


xenon-arc weathering testing for automotive white coatings

Compared with conventional stabilization solutions, the product showed:


1

Compared with conventional stabilization solutions, the product showed:

2

Better overall performance during a 3,600-hour accelerated aging evaluation


These results help support improved appearance retention and extended service life for automotive coatings, outdoor finishes, premium adhesives, and TPU materials exposed to demanding environments.






Liquid Form 

with Excellent Compatibility

03

PART.THREE

RIASORB® UV-571UL



Compared with traditional solid UV absorbers, the liquid form of RIASORB® UV-571UL offers several practical processing benefits:


1

Easier and more accurate dosing

2

Faster and more uniform dispersion

3

Support for higher additive loading levels to enhance formulation flexibility

4

Excellent compatibility with reduced risk of haze or crystallization, even under low-temperature or high-concentration conditions


These advantages are particularly beneficial for polyurethane systems, sealants, elastomers, and other complex formulations where processing stability and manufacturing efficiency are important.










04

PART.FOUR

Enhanced Environmental, Health, 

and Safety Profile

RIASORB® UV-571UL




As sustainability requirements and global regulations continue to evolve, environmental and safety considerations are becoming increasingly important in additive selection.

RIASORB® UV-571UL supports these requirements through several advantages:


1

Does not require GHS hazard labeling

2

Solvent free

3

Classified as non-dangerous goods for transportation and storage

4

This makes the product particularly suitable for:Coating systems with strict VOC control requirements

5

Applications prefer to low content of inflammable chemicals.

6

Green and low-carbon material solutions




Recommended Applications


RIASORB® UV-571UL is recommended for a broad range of applications, including:


1

Thermoplastic polyurethane (TPU), foamed PU, and elastomers

2

Adhesives and sealants, including EVA, PVB, acrylic, polyurethane, and silane-modified polymer systems

3

Solvent-based coatings, UV/EB coatings, and selected waterborne systems

4

Rigid and plasticized PVC, PVB, PMMA, PVDC, EVOH, EVA, and hot cured unsaturated polyester systems

5

Spin finishes for PA, PET, PUR, and PP fibers, rubber, optical adhesives, optical components, and specialty optical chemicals



Formulation Guidelines

Because the optimal dosage depends on the resin system, pigment selection, and targeted weathering performance, there is no universal recommendation for all formulations.


Rianlon recommends an initial evaluation range of 0.5%–2.0%. Final optimization should be determined based on key performance indicators such as:

  • Yellowing resistance

  • Gloss retention

  • Mechanical property retention after aging


Request Samples and Technical Support

For formulators seeking an efficient liquid UV absorber for TPU, adhesives, automotive coatings, or transparent polymer systems, RIASORB® UV-571UL represents a reliable and versatile solution.


To request samples or discuss your application requirements, please contact the Rianlon technical team for further support and formulation recommendations.



About Rianlon

Rianlon is a leading global supplier of anti-aging additives and application technologies for polymer materials, and the first publicly listed company in China’s polymer stabilization industry (Stock Code: 300596).


Supported by six manufacturing bases, Rianlon provides a comprehensive portfolio of antioxidants (RIANOX®), light stabilizers (RIASORB®), and integrated stabilization solutions (U-pack®). With extensive expertise in thermo-oxidative stabilization and weathering protection for polymer materials, Rianlon is committed to helping customers improve product quality, optimize cost efficiency, and accelerate new product development through customized solutions and technical support.




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