Introduction: What Is UV Absorber 326?

Ultraviolet (UV) radiation is one of the major causes of polymer degradation. Long-term exposure to sunlight can accelerate oxidation reactions in plastics, coatings, and other organic materials, resulting in:

• Color fading
• Yellowing
• Surface cracking
• Loss of mechanical strength
• Reduced product lifetime

To overcome these challenges, UV absorbers are widely added into polymer formulations to protect materials from UV-induced degradation.

UV Absorber 326 (UV-326) is a high-performance benzotriazole-based ultraviolet absorber designed to provide excellent light stability for plastics and organic substrates. It is also known as 2-(5-chloro-2H-benzotriazol-2-yl)-6-(tert-butyl)-4-methylphenol, with CAS No. 3896-11-5.

Compared with traditional UV absorbers such as UV-531 and other benzophenone-based products, UV-326 provides stronger UV protection, lower volatility, and better long-term weathering performance, making it an ideal choice for demanding polymer applications.

Physical and Chemical Properties of UV-326

Basic Information

Product Name: UV Absorber 326
Chemical Family: Hydroxyphenyl Benzotriazole UV Absorber
CAS No.: 3896-11-5
Molecular Formula: C17H18ClN3O
Molecular Weight: 315.8 g/mol
Appearance: Light yellow crystalline powder
Melting Point: Approximately 137–142°C

UV-326 has excellent thermal stability, low volatility, and good compatibility with various polymer systems. It can effectively absorb UV radiation in the 270–380 nm range while maintaining good transparency in visible light applications.

How Does UV-326 Protect Polymers from UV Damage?

UV-326 works through a UV energy absorption and conversion mechanism.

When polymer materials are exposed to sunlight, high-energy UV radiation can break chemical bonds inside polymer chains and generate free radicals. These reactions lead to aging, discoloration, and mechanical degradation.

The benzotriazole structure of UV-326 absorbs harmful UV energy through electronic excitation.

The process is:

UV radiation → UV-326 absorption → molecular excitation → energy conversion → harmless heat release

The molecule then returns to its stable state and continues absorbing UV energy repeatedly.

This efficient energy conversion mechanism allows UV-326 to provide long-term protection for polymer materials.

UV-326 vs Other UV Absorbers: Why UV-326 Has Advantages

UV absorbers include several chemical families:

• Benzotriazole UV absorbers
• Benzophenone UV absorbers
• Triazine UV absorbers
• Oxanilide UV absorbers

Among these, UV-326 is considered a high-performance benzotriazole UV absorber.

UV-326 vs UV-531

UV-531 is a benzophenone-type UV absorber commonly used in general plastics and cost-sensitive applications.

Performance	UV-326	UV-531
Chemical Type	Benzotriazole	Benzophenone
UV Protection	Excellent	Good
UV Range	270–380 nm	270–360 nm
Long-Term Weather Resistance	Excellent	Moderate
Thermal Stability	Higher	Lower
Volatility	Lower	Higher
Engineering Plastics	Suitable	Limited
Outdoor Applications	Excellent	General

Why UV-326 Performs Better:

1. Stronger UVA Protection

UV-326 provides excellent absorption in the longer wavelength UV region, especially 300–400 nm, which plays an important role in outdoor polymer aging.

2. Better Thermal Stability

During plastic processing, materials often experience high temperatures.

UV-326 has:

• Low volatility
• High resistance to thermal degradation
• Better retention during extrusion and molding processes

This makes it suitable for engineering plastics and polyolefin processing.

3. Longer Outdoor Service Life

Compared with conventional benzophenone UV absorbers, UV-326 provides more durable protection against:

• UV radiation
• Weather exposure
• Color fading
• Surface deterioration

Main Applications of UV-326

1. Polyolefin Applications (PP and PE)

UV-326 is widely used in:

• Polypropylene (PP)
• Polyethylene (PE)
• Plastic films
• Injection molded products

Benefits:

• Prevents yellowing
• Maintains mechanical strength
• Improves outdoor durability

Typical applications include:

• Agricultural films
• Outdoor containers
• Plastic components
• Packaging materials

UV-326 is especially suitable for polyolefin systems because of its low volatility and strong thermal resistance during processing.

2. Engineering Plastics

UV-326 is commonly used in:

ABS

Applications:

• Automotive components
• Electrical housings
• Consumer products

Advantages:

• Reduces surface cracking
• Prevents color change
• Improves outdoor stability

Polycarbonate (PC)

Applications:

• Transparent sheets
• Optical materials
• Protective covers

Advantages:

• Maintains transparency
• Reduces UV degradation

PET and Other Polyester Materials

UV-326 improves:

• Light stability
• Color retention
• Long-term durability

3. Automotive Materials

Modern automotive plastics require long-term UV resistance.

UV-326 is used in:

• Exterior plastic parts
• Interior components
• Coatings
• Adhesives

Advantages:

• Better appearance retention
• Reduced aging
• Longer service life

For automotive applications, UV-326 is often combined with HALS light stabilizers to achieve advanced weathering performance.

4. Coatings and Paints

UV-326 is widely used in:

• Industrial coatings
• Automotive coatings
• Wood coatings
• Architectural coatings

It helps protect coatings from:

• Loss of gloss
• Cracking
• Yellowing
• Color fading

5. Adhesives and Sealants

In UV-sensitive adhesive systems, UV-326 helps maintain:

• Adhesive strength
• Appearance stability
• Long-term performance

Applications include:

• Electronic adhesives
• Construction sealants
• Industrial bonding materials

Why Choose Ecochem for UV-326?

Choosing the right UV absorber supplier is not only about product quality. Technical support, supply stability, and customer service are equally important.

1. High-Quality UV-326 Supply

Ecochem focuses on providing reliable UV stabilizer solutions with:

• Stable quality control
• Consistent performance
• Professional product documentation

Customers can confidently use Ecochem UV-326 in research, formulation development, and industrial production.

2. Small Quantity Samples for Laboratory Testing

Product development often requires testing before large-scale purchasing.

Ecochem supports:

• Laboratory samples
• Small batch orders
• Formula evaluation
• Application testing

Benefits:

• Lower development costs
• Faster formulation screening
• Reduced project risk

Whether you are developing a new polymer formulation or evaluating UV protection performance, Ecochem provides flexible sample solutions.

3. Professional Technical Support

The effectiveness of UV-326 depends on:

• Polymer type
• Processing temperature
• UV exposure conditions
• Additive combination

Ecochem provides technical assistance including:

• Product selection recommendations
• Application guidance
• Dosage optimization
• UV stabilizer system suggestions

For high-performance applications, Ecochem can also recommend combination systems such as:

UV Absorber + HALS + Antioxidant

to achieve maximum weather resistance.

4. Reliable Logistics and Global Supply Capability

Ecochem understands that chemical customers require:

• Stable supply
• Fast response
• Flexible packaging
• Reliable delivery

Advantages include:

• Small quantity shipment support
• Bulk supply capability
• International logistics coordination
• Long-term supply planning

5. Long-Term Partnership Approach

Ecochem is committed to supporting customers throughout the product development cycle:

From:

Laboratory testing

↓

Formula optimization

↓

Pilot production

↓

Commercial manufacturing

Ecochem provides continuous support to help customers achieve stable and successful applications.

Conclusion

UV Absorber 326 (UV-326) is a high-performance benzotriazole UV stabilizer that provides outstanding protection against UV-induced polymer degradation.

Compared with traditional UV absorbers such as UV-531, UV-326 offers:

• Stronger UV absorption
• Better thermal stability
• Lower volatility
• Superior weather resistance
• Longer material service life

It is widely used in:

• Polyolefins
• Engineering plastics
• Automotive materials
• Coatings
• Adhesives
• Outdoor polymer products

For customers looking for reliable UV-326 solutions, Ecochem provides not only high-quality UV absorbers but also flexible sample support, technical expertise, reliable logistics, and long-term cooperation.

Choose Ecochem as your trusted UV stabilizer partner and improve the durability, appearance, and performance of your polymer products.