UV-C Resistant PP Plastic Pellets for Water Tanks

Properties of UV-C Resistant PP Material
Ordinary polypropylene (PP) undergoes rapid photo-oxidation under UV-C irradiation, leading to molecular chain breakage (degradation), which manifests as:
Rapid embrittlement and powdering
Sharp decline in mechanical strength
Surface cracking and discoloration

UV-C resistant modified PP significantly improves the following properties through the addition of stabilizer systems:
Excellent UV-C Stability:
Core feature: Capable of withstanding high-intensity UV-C irradiation for extended periods (hundreds to thousands of hours) without significant deterioration in mechanical performance or appearance. This is the fundamental difference from ordinary PP.

Retention of basic mechanical properties:
While providing anti-aging performance, it retains PP’s advantages such as light weight, chemical resistance (especially acid and alkali resistance), excellent electrical insulation, and ease of processing (injection molding, extrusion).
Rigidity and toughness can be adjusted according to grade.

High transparency (optional):
For applications requiring UV-C penetration (e.g., sterilization equipment covers), it can be made in high-transparency or semi-transparent grades to ensure effective UV-C transmission. This requires high material purity and careful formulation.

Heat resistance:
PP’s heat resistance is generally around 100–130°C. UV-C modification usually does not reduce heat resistance, and some stabilizers can even enhance thermal-oxidative stability.

Safety and compliance:
For applications in specific fields (such as food or medical), stabilizers must comply with FDA, RoHS, EU 10/2011, and other regulations, ensuring non-toxicity and no migration.
How UV-C Resistance is Achieved – Key Modification Methods

UV-C resistance is primarily achieved by adding light stabilizers into the PP matrix, which act through different mechanisms:
Ultraviolet Absorbers (UVAs):
Function: Absorb high-energy UV-C photons like a “sponge” and release them harmlessly as heat.
Common types: Benzotriazole, benzophenone. For high-energy UV-C, high-efficiency types with matching absorption bands must be selected.

Hindered Amine Light Stabilizers (HALS):
Function: The most effective and critical stabilizers. They capture free radicals generated during PP photo-oxidation, interrupting chain reactions and providing “regenerative” long-term protection.
Features: Small amounts significantly enhance weather resistance and can act synergistically with UVA.

Inorganic Nanoparticles / Pigments:
Function: Titanium dioxide (TiO₂), especially rutile type, is an excellent physical UV shield, reflecting and scattering UV rays. Carbon black is a strong UV absorber.

Note: Adding these will make the material opaque.

Formulation and Processing Optimization:
Use high-purity PP resin to reduce oxidation-inducing sites such as catalyst residues.
Ensure uniform dispersion of stabilizers in the matrix (using compounding and granulation techniques).

Main Applications
The core application scenarios for UV-C resistant PP revolve around environments that utilize or resist UV-C radiation:

UV Sterilization Equipment:
Core market: This is the largest demand segment.

Specific products:
Home appliances: UV-C lamp covers, water tanks, air duct components (for air purifiers, dishwashers, water purifiers, humidifiers, etc.)
Medical / Industrial: Medical sterilization cabinets, surface sterilization equipment, UV sterilization module housings, cavities, and brackets

Special Lighting and Laboratory Equipment:
UV-C lamps: Require transparent and aging-resistant lamp tube covers and fixtures
Laboratory instruments: Components and sample racks exposed to UV-C
Semiconductor manufacturing: Certain instruments used in cleanroom environments

High-Weather-Resistance Outdoor Products:
Although UV-C is mostly blocked by the atmosphere, in regions with extreme UV exposure (high altitudes, equatorial areas) or specific industrial environments, modified PP can be used for outdoor components with very high durability, far surpassing ordinary PP.