For outdoor use, cable materials must be able to withstand challenging environments. UV-cross-linked polyethylene compounds (UV-XLPE) were developed precisely to address this need. By enhancing protection against ultraviolet (UV) radiation, they provide cables with a longer and more reliable outdoor service life.
This article systematically explains the performance characteristics of UV-resistant XLPE, its impact on cable performance, and why this material has become an indispensable component of modern outdoor cable systems.
UV-cross-linked polyethylene is an improved version of traditional cross-linked polyethylene (XLPE), designed to enhance its resistance to UV radiation. By incorporating UV stabilizers into the polyethylene matrix, it significantly mitigates the molecular damage caused by long-term sunlight exposure, thereby maintaining the material's mechanical and electrical integrity.
In practical applications, the primary function of UV-cross-linked polyethylene is to prevent cable aging, cracking, and embrittlement caused by UV radiation, ensuring that the cable remains flexible and reliable even in environments exposed to long-term direct sunlight.
Cables installed outdoors are often exposed to sunlight. UV radiation gradually breaks down the chemical structure of non-UV-resistant materials, leading to degraded cable performance and shortened service life.
The mechanisms of UV light action include:
Photooxidation: This initiates polymer oxidation, resulting in molecular chain breakage.
Surface Cracking: This causes microcracks to form as elasticity decreases.
Color Change: This causes discoloration due to degradation of pigments and additives.
Powdering: This causes the surface layer to decompose, leaving a powdery residue.
Loss of Flexibility: This causes the material to become hard and brittle.
Degradation of Electrical Performance: This weakens the insulation properties of the sheath after water absorption.
Example of a typical degradation process (unprotected PVC material):
| Exposure duration | Major Changes |
| 1–3 months | Surface hardening and slight discoloration |
| 6–12 months | Cracks and decreased tensile strength |
| 12–24 months | Noticeable chalking and surface peeling |
| 2 years and above | Severe insulation degradation and functional failure |
The degradation rate is affected by factors such as geographic location, UV intensity, material type, and installation angle.
UV protection is particularly critical in the following scenarios:
· Solar photovoltaic installations
· Outdoor lighting and urban infrastructure
· Telecommunications and signal tower systems
· Open-air power transmission lines
· Offshore and oil drilling environments
Cables lacking UV protection often experience insulation degradation or mechanical damage before reaching their designed lifespan, increasing maintenance costs and posing safety risks.
Common signs of UV degradation in the field include:
· Surface cracking or peeling
· Blurred printed markings
· Hardening or brittle sheathing
· Surface powdery residue
· Abnormal decrease in insulation resistance
Once these problems occur, the entire cable must be replaced.
The material effectively resists structural degradation caused by sunlight and UV radiation, significantly extending the cable's outdoor service life.
It maintains stable mechanical and electrical properties even in high temperatures or environments subject to extreme temperature fluctuations.
It offers excellent resistance to rain, snow, high humidity, and temperature fluctuations, ensuring continuous cable operation.
The insulation layer's enhanced tensile and abrasion resistance allows it to withstand complex construction and operating conditions.
Extended service life and reduced failure rates effectively reduce maintenance and replacement frequency.
UV-grade cross-linked polyethylene compounds must meet multiple international standards to ensure reliable performance in solar, telecommunications, and industrial environments.
| Items | Requirements | Test standards |
| Tensile Strength Retention | ≥70%(after 720h of UV exposure) | ISO 4892-3 / ASTM G154 |
| Elongation at Break Retention | ≥65%(after 720h of UV exposure) | IEC 60811-501 |
| Surface Condition | No cracks or chalking | IEC 60811-605 |
| Parameters | scope | standard |
| Tensile Strength | 12–20 MPa | ASTM D638 |
| Elongation at Break | ≥250% | ASTM D638 |
| Conditions | Typical values | standard |
| 135°C/168h Aging Retention | ≥70% | IEC 60811-401 |
| Continuous Operating Temperature | ≤90℃ | IEC 60228 |
| Short-Circuit Temperature | ≤250℃ | IEC 60332-1 |
| index | Numerical | Test Method |
| Volume resistivity | ≥10^14Ω·cm | ASTM D257 |
| Dielectric strength | ≥20 kV/mm | ASTM D149 |
| Dielectric loss angle（tanδ） | ≤0.002 | IEC 60250 |
| Item | Numerical | standard |
| Water Absorption (24h @ 23°C) | ≤0.1% | ISO 62 |
| Oxidation Induction Time (OIT) | ≥20 min@200℃ | ASTM D3895 |
| project | index | standard |
| Oxygen Index (LOI) | ≥28% | ISO 4589-2 |
| Smoke Density (Ds max) | ≤200 | IEC 61034-2 |
| Halogen Acid Content | ≤0.5% | IEC 60754-1 |
Comprehensive performance goals:
| Classification | Technical Specifications |
| UV aging resistance | ≥70% TS/EB Retention (720h UV Exposure) |
| Mechanical properties | ≥12MPa Tensile Strength, ≥250% Elongation at Break |
| Thermal stability | ≥70% Retention (135°C/168h) |
| Electrical properties | ≥10^14Ω·cm Volume Resistivity, ≥20kV/mm Dielectric Strength |
| Water absorption | ≤0.1% LOI ≥28%, Halogen-free Formula |
| Flame retardant properties | Technical Specifications |
UV-cross-linked polyethylene compounds are widely used in various cable systems exposed to the elements:
Solar cables: Maintain stable performance under intense sunlight and high temperatures.
Outdoor power cables: Suitable for construction, infrastructure, and power grid projects.
Communication cables: Enhance long-term reliability in open air and high-humidity environments.
UV-cross-linked polyethylene combines high weather resistance, excellent thermal stability, and long-lasting mechanical strength, making it an ideal solution for various outdoor cable systems.
Using this material not only extends cable life but also significantly reduces maintenance and replacement costs, ensuring continuous and safe operation of systems in complex environments.
It is a material modified by adding UV stabilizers to ordinary cross-linked polyethylene to effectively resist UV damage.
Long-term exposure can cause material aging, cracking, and insulation degradation, thereby shortening cable life.
It offers high UV resistance, strong thermal stability, excellent weather resistance, and outstanding mechanical properties.
It is primarily used in solar photovoltaic cables, communications cables, outdoor power cables, and industrial equipment cables.
By enhancing UV resistance and mechanical toughness, it ensures stable and reliable operation in extreme environments.
