Views: 0 Author: Site Editor Publish Time: 2026-03-02 Origin: Site
PP/PE: General-grade PP/PE is prone to UV-induced chain scission. Opt for copolymer PP or metallocene PE (instead of homopolymer) for better toughness. For modified PP (e.g., glass fiber-reinforced PP like S3615), prioritize factory UV-stabilized grades to avoid rework.
ASA/PVC: The gold standard for outdoor plastics. ASA (an alternative to ABS) resists yellowing and chalking for 10+ years outdoors with minimal additives, making it ideal for high-demand products like outdoor furniture and building profiles.
ABS/PA6/PA66: Poor inherent weather resistance—ABS’s butadiene phase degrades under UV light, and PA is prone to hydrolysis. Replace ABS with ASA for outdoor use; if PA is necessary, choose hydrolysis-resistant grades.
PC: Good UV resistance but susceptible to stress cracking. Pair with low-stress processing and mild UV additives for outdoor applications.
| Additive Type | Function | Recommended Outdoor-Grade Models | Loading Ratio | Synergy Tip |
|---|---|---|---|---|
| UV Absorber (UVA) | Absorbs 290-400nm UV light (the damaging band) and converts it to heat | Benzotriazoles (UV326/UV327), Benzophenones (UV531) | 0.2-0.5% | Mix 1:1 with HALS for best results |
| Hindered Amine Light Stabilizer (HALS) | Traps free radicals to stop degradation chain reactions (long-term weather resistance core) | Low molecular (UV770/UV944), High molecular (UV292/UV119) | 0.1-0.4% | High molecular HALS = better migration resistance |
| Antioxidant Package | Inhibits thermal/photo-oxidation (protects during processing and use) | Primary (1010/1076) + Secondary (168) | 0.1-0.3% + 0.2-0.5% | Never use single antioxidant—blend for synergy |
Hydrolysis Inhibitor (CDI): 0.2-0.5% for PA/PC to prevent cracking in humid outdoor environments.
Inorganic Pigments: Carbon black (2-3%) is a natural UV shield for dark plastics (PP/PE); rutile titanium dioxide (for light colors) boosts UV blocking and hiding power. Avoid organic pigments—they fade and degrade under UV light.
Tougheners (POE/EPDM): 5-10% for PP/PE to reduce brittleness and cracking from extreme temperature cycles (-40°C to 80°C).
Control Processing Temperature: Avoid overheating (e.g., PP ≤250°C, ASA ≤260°C) to prevent thermal decomposition of additives and plastic chains.
Reduce Shear Stress: Lower screw speed, increase back pressure, and use low-shear screw designs to minimize molecular chain breakage.
Optimize Packing & Cooling: Use moderate packing pressure (80-120MPa for PP/PE) and sufficient cooling time to eliminate internal stress from uneven cooling.
Eliminate Weld Lines: Add more gates, optimize gate location, and increase melt temperature to strengthen weld lines—they are prone to UV degradation and cracking.
Post-Processing Care: Avoid sanding/polishing outdoor plastic surfaces (it disrupts the additive distribution layer). Use weather-resistant adhesives/primers for bonding or assembly.
Use outdoor-grade polyester or epoxy-polyester hybrid powder coatings—they offer excellent UV resistance, salt spray resistance (≥1000h), and scratch resistance.
For PP/PE (low surface energy), pre-treat with corona discharge to improve coating adhesion. Powder coating is ideal for garden tools, outdoor lighting, and automotive exterior parts.
Adopt 2/3-layer co-extrusion: a thin outer layer (≥0.2mm) of weather-resistant ASA/UV-stabilized PP, and a core layer of standard modified plastic. This balances durability and cost—perfect for outdoor building profiles and plastic sheets.
Fluorocarbon coatings (PVDF) offer 20+ years of outdoor durability with no chalking or fading. They are the top choice for high-end products like photovoltaic component housings and architectural plastics—worth the higher cost for long-term value.
For low-budget small products (e.g., plastic garden stakes), spray weather-resistant micro-powder wax (e.g., Clariant Ceridust 9615F) on the surface. It forms a thin protective layer to reduce UV exposure and water erosion—an easy, affordable upgrade.
Round All Corners: Use a radius of R≥0.5mm for all sharp edges—stress concentration at sharp corners speeds up UV cracking 3-5x faster than smooth surfaces.
Uniform Wall Thickness: Keep thickness deviation ≤10% to avoid uneven cooling and internal stress. Thin walls lose additives faster, while thick walls trap stress.
Add Drainage: Design drain holes and chamfers to prevent water/dust accumulation—standing water accelerates additive hydrolysis, and dust absorbs UV light to cause local degradation.
Optimize Ribs: Use wide, short ribs instead of narrow, tall ones. Rib thickness should be ≤70% of the main wall to avoid stress at the root.
Seal Gaps/Catches: Fill gaps and seal plastic catches with weather-resistant sealant to prevent water/dust from entering and causing internal aging.
Xenon Arc Aging Test (ISO 4892-2/SAE J2527): Simulates full-spectrum UV, temperature cycles, and humidity—test for 500/1000/2000h. Pass criteria: ΔE (color change) ≤2, no chalking/cracking, mechanical strength retention ≥80%.
UV Aging Test (ISO 4892-3): Fast validation of UV additive performance—ideal for prototype testing.
Temperature Cycle Test (GB/T 2423.22): Simulates -40°C to 80°C cycles to test anti-brittleness and cracking resistance.
Field Exposure Test: The ultimate validation—test products in high-UV regions (e.g., Hainan, Florida) for 6/12 months. It reflects real-world aging more accurately than lab tests.
Material is the foundation: Choose weather-resistant base resins and factory-modified UV-stabilized grades (e.g., S3615).
Additives are the core: Use a synergistic blend of UVA, HALS, and antioxidants—never single additives.
Processing is the guarantee: Minimize internal stress to avoid weak points for UV attack.
Surface protection is the upgrade: Add a physical barrier for high-demand products.
Testing is the validation: Always test prototypes with accelerated aging before mass production.
