Chiguard®: UV Stabilizers
Ultraviolet (UV) radiation from sunlight gradually degrades polymers, causing yellowing, embrittlement, and performance loss. Chiguard® UV stabilizers effectively prevent UV-induced damage and significantly extend product lifespan in outdoor environments.
Why Do We Need UV Stabilizers?
- Prevent yellowing and discoloration
- Reduce embrittlement and loss of strength
- Maintain long-term appearance and performance
They act as an invisible shield, protecting against sunlight, oxygen, and heat.
UVA and HALS
UV Absorbers (UVA)
UV absorbers protect polymers by absorbing harmful ultraviolet radiation and dissipating the absorbed energy as harmless heat before photochemical degradation occurs.
They are especially important for transparent applications where optical clarity and color stability are critical.
- Absorb harmful UV radiation and convert it into harmless thermal energy
- Reduce polymer photodegradation before it begins
- Preserve transparency, gloss, and color stability
- Common chemistries include benzophenones, benzotriazoles, and triazines
Hindered Amine Light Stabilizers (HALS)
HALS do not absorb UV radiation directly. Instead, they inhibit photo-oxidative degradation by scavenging free radicals generated during polymer weathering.
Through a regenerative stabilization cycle, HALS continuously interrupt the propagation stage of oxidation, providing long-term protection even at relatively low concentrations.
- Scavenge free radicals and stop oxidation reactions
- Highly effective even at low concentrations
- Delay aging, prevent embrittlement, maintain performance
UVA + HALS: A Complementary Stabilization System
- UVA: Absorb harmful UV radiation and convert the absorbed energy into harmless heat before photochemical reactions occur. Their primary function is to reduce the amount of UV energy reaching the polymer. UVA do not scavenge free radicals or reverse existing degradation, making them particularly suitable for transparent plastics, films, and clear coatings.
- HALS: Capture and neutralize free radicals (such as R•, ROO•), using a regenerative cycle to suppress the propagation step of autoxidation. They do not absorb UV themselves. Especially effective for thick, colored, or opaque materials. Acidic components may deactivate HALS, requiring acid-resistant grades or co-additives.
Synergistic Effect: Combining UVA and HALS reduces both surface photodamage and internal oxidative degradation. This significantly lowers yellowing, chalking, cracking, and embrittlement—helping retain gloss and mechanical properties, and extending outdoor service life.
Together, they form a comprehensive stabilization system for demanding outdoor applications.
Key Applications
- Plastics: Outdoor furniture, parts, accessories
- Coatings: Automotive and industrial surfaces
- Adhesives & Sealants
- Textiles: Awnings, outdoor fabrics, apparel
Impact on Product Lifespan
- Enhances weatherability and durability
- Slows down degradation
- Maintains long-term performance and appearance
- Meets market demand for high-weatherability products
Video
Can you distinguish between UVA and HALS?
Test your knowledge with our quick interactive quiz.
Start Quiz
