ZC-3111 Peroxide Crosslinkable XLPE Insulation Compound for Medium Voltage Cable Up to 35kV

1. Peroxide Type and Crosslinking Mechanism

Peroxide crosslinking converts thermoplastic polyethylene into a three-dimensional network, delivering heat resistance, mechanical strength, and long-term reliability that uncrosslinked PE cannot match. The peroxide decomposes at extrusion temperature to generate free radicals, which abstract hydrogen atoms from PE chains to form carbon-carbon crosslinks.

Selection logic: DCP is the industry-standard choice for cables ≤35kV, offering the best balance of performance, processability, and cost. For thicker insulation walls (>5mm) or higher voltage classes, consider DHBP or BIPB for improved scorch safety and lower volatile content. For cables up to 35kV, start with 2.0–2.5 phr DCP; increase toward 3.0 phr for thicker insulation.

2. Insulation Thickness and Voltage Class

For 26/35kV cables, the insulation thickness typically reaches 10.5mm for cross-sections of 50mm² and above. Thicker insulation requires higher gel content (>85%) and stricter control of peroxide migration and by-product removal during degassing.

3. Gel Content and Crosslinking Degree

Gel content directly indicates crosslinking completeness. For medium voltage cables (≤35kV), the target gel content is ≥85% per ASTM D2765. ZC-3111 delivers a typical gel content of 86%. Incomplete crosslinking results in reduced mechanical strength, lower dielectric performance, and increased risk of cable failure under thermal stress. Monitor gel content for every production batch.

4. Processing Temperature Profile

Peroxide crosslinking requires precise temperature control across the extrusion and curing stages. The recommended barrel temperature profile for ZC-3111 is:

The CV (continuous vulcanization) tube temperature should be maintained at 160–190°C for complete peroxide decomposition and crosslinking. The compound is compatible with conventional three-layer co-extrusion lines with a draw ratio of 20:1 to 30:1.

5. Cleanliness and Impurity Control

Insulation compound cleanliness is critical for medium voltage cable performance. Impurities and contaminants can cause partial discharge, leading to premature insulation failure. ZC-3111 is produced in a closed system with loss-in-weight feeders to ensure stable precision and minimal contamination. Impurity particle size distribution should be verified per batch. For 35kV cables, ultra-clean grades with stricter particle count limits are recommended.

6. Degassing and By-Product Removal

Peroxide crosslinking generates volatile by-products (e.g., acetophenone, cumyl alcohol) that must be removed through a degassing process. Incomplete degassing can cause voids, odors, and reduced dielectric performance. Degassing is typically performed at 60–80°C for 24–72 hours, depending on insulation thickness. For 35kV cables with 10.5mm insulation, extended degassing may be required.

7. Scorch Safety and Shelf Life

Scorch (premature crosslinking during extrusion) can cause surface defects and equipment blockage. The compound should have a scorch time (ts2) of >8 minutes at processing temperature. Store ZC-3111 at room temperature in a clean, dry, and ventilated environment. Best use within six months from the date of production. Packaging is 500kg per package, inner lined with plastic sealed film bag, corrugated carton with tray at the bottom.

8. Standards and Testing

Specify applicable standards: IEC 60502-2, GB/T 12706.2, or project-specific requirements. Key test methods include:

• Gel content: ASTM D2765

• Dielectric strength: IEC 60243-1

• Volume resistivity: IEC 60093

• Hot set: IEC 60811-2-1

• Tensile strength and elongation: IEC 60811-1-1

• Impurity particle count: per project specification

Request a Certificate of Analysis (COA) for each batch, including gel content, dielectric strength, volume resistivity, and impurity data.

Technical Specifications

Note: Typical values are measured under fully crosslinked conditions. Performance may vary if sufficient crosslinking is not achieved. Confirm actual batch data before production.

Typical Applications

• 35kV and below XLPE insulated power cable insulation layer

• Medium voltage distribution cables (3.6/6kV to 26/35kV)

• Underground and duct-laid MV power cables

• Substation and industrial power distribution cables

• Renewable energy collection cables requiring peroxide-crosslinked XLPE insulation

ZC-3111    Peroxide XLPE Insulation Compound for MV Cable up to 35kV

This material is a kind of crosslinkable polyethylene insulation compound. It is made of high quality PE resin, dicumyl peroxide agent and antioxidant agent by plasticizing granulation. Production process uses the closed system;  Loss-in-weight  Feeder  which  guarantees  stable  precision  of  components.  It  has  stable  physical  and chemical index and good processing property.

Application: 35kV crosslinkable cable insulation; Maximum working temperature is 90C.

Property

Impurity content

Particles number<C1 qualified. BetweenC1 and C2, re-inspection. Particles number> C2, unqualified.

Processing

Recommend to use conventional extruder (three layers co-extrusion, draw ratio is from 20:1 to 30:1) and other equipments need to be adjusted according to the circumstance.

- Above temperature is only for reference.

Storage

keep at room temperature; Storage environment should be clean, dry and ventilated; Best use within six months from the date of production.

Product packing

500kg in each package; Inner lined with plastic sealed film bag; Corrugated carton with tray at the bottom.