Modified High-Density Polyethylene (HDPE) Coil Tube

Product Overview

The Modified High-Density Polyethylene (HDPE) Coil Tube is a versatile, flexible tubing solution engineered for demanding industrial, municipal, and infrastructure applications. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this product combines the inherent chemical resistance and mechanical durability of HDPE with proprietary modifications that enhance its thermal stability, environmental stress crack resistance (ESCR), and long-term hydrostatic pressure performance. Supplied in continuous coil form, the product offers superior flexibility, reduced field waste, and simplified installation compared to straight-length alternatives.

Material & Properties

The base resin system consists of high-purity HDPE (ISO 1167 grade PE 100 or PE 100-RC) subjected to controlled modification processes. The modification typically involves the incorporation of functional additives—including UV stabilizers (HALS and benzophenone-type), antioxidants (phenolic and hindered amine), carbon black masterbatch for light protection, and nucleating agents to optimize crystallinity and spherulite morphology.

Specifications

Parameter Specification Test Standard
Outer Diameter (OD) 16 mm – 63 mm (standard range) ISO 4427-1
Wall Thickness (SN100) 1.8 mm – 5.8 mm ISO 12162
Wall Thickness (SN160) 2.7 mm – 8.6 mm ISO 12162
Wall Thickness (SN250) 4.2 mm – 13.4 mm ISO 12162
Pressure Rating (20°C) 1.0 MPa / 1.6 MPa / 2.5 MPa ISO 12162
Coil Length 50 m – 500 m (configurable) Manufacturer specification
Coil Inner Diameter 150 mm – 300 mm Manufacturer specification
Color Black (with blue or white color banding) ISO 1043
Traceability Marking Co-extruded or printed (producer ID, material grade, SDR, date code) ISO 1167
Hydrostatic Burst Test ≥ 2× design pressure for 1 hour (100% inspection) ISO 1167
Dimensional Tolerance ±0.1 mm OD; ±10% wall thickness ISO 4427-2

Manufacturing Process

The production of Modified HDPE Coil Tube follows a tightly controlled extrusion-based process ensuring consistent wall geometry, uniform material distribution, and reliable long-term performance:

  1. Raw Material Preparation: Virgin HDPE resin (PE 100 or PE 100-RC) is blended with a masterbatch containing carbon black (2.0–2.5%), HALS UV stabilizers, phenolic antioxidants, and processing aids in a high-shear mixer at controlled temperatures (≤ 130°C) to prevent premature degradation.
  2. Feed System: The compounded pellet blend is fed via a volumetric feeder into a single-screw extruder with a compression ratio of 3.0–3.5:1 and an L/D ratio of 30–35:1.
  3. Extrusion & Melt Homogenization: The barrel temperature profile is maintained at 180–210°C across feed, compression, and metering zones. A die clearance of 0.1–0.3 mm ensures dimensional accuracy. A vacuum degassing port removes entrained volatiles.
  4. Die Forming: A precision-engineered annular die with controlled gap width (±0.01 mm) produces the tubular extrudate. A calibration die with segmented air rings maintains concentricity.
  5. Co-extrusion (Optional): A thin inner layer of food-grade or conductive material may be co-extruded for specialized applications (e.g., potable water compliance or electrostatic dissipation).
  6. Calibration & Cooling: The extrudate passes through a vacuum calibration tank where controlled negative pressure (−0.5 to −0.7 bar) sets the final dimensions. Subsequent water bath cooling (20–25°C) ensures controlled crystallization kinetics.
  7. Traceability Marking: A co-extrusion marking unit or ink-jet printer applies producer identification, material grade, SDR, nominal pressure rating, and production date code at 1-meter intervals.
  8. Coiling & Winding: The cooled tube is wound onto a pay reel using a tension-controlled winding system that maintains a constant coil diameter. Tension is regulated to prevent flattening or ovality exceeding 2%.
  9. Quality Inspection: Each coil undergoes 100% hydrostatic pressure testing at 1.5× design pressure for a minimum of 1 hour. Random samples are subjected to non-destructive testing (NDT) including ultrasonic wall thickness measurement and visual inspection for surface defects.
  10. Packaging: Coils are wrapped in protective polyethylene film and secured with steel strapping. Shipping pallets are labeled with full traceability documentation.

Applications

Quality Certifications & Compliance

The Modified HDPE Coil Tube product line adheres to and is certified against the following international standards and regulatory frameworks:

Unique Selling Points

1. Superior ESCR Through Molecular Modification: The proprietary modification process optimizes the molecular weight distribution (MWD) and introduces controlled short-chain branching, resulting in ESCR values exceeding 500 hours — significantly outperforming standard PE 100 grades and ensuring decades of reliable service life.

2. Continuous Coil Format Advantage: The coil supply format enables trenchless installation methods including direct burial, directional drilling, and pull-in methods, reducing installation time by up to 60% compared to straight-length pipe with butt-fusion joints.

3. Full Traceability: Every meter of tubing carries co-extruded identification marking in accordance with ISO 1167 requirements, enabling complete lifecycle traceability from raw material batch to final installation location.

4. Long-Term Hydrostatic Pressure Performance: Modified HDPE coils maintain ≥ 10 MPa hydrostatic strength at 20°C for 100,000 hours (design life), validated through ISO 1167 long-term hydrostatic strength (LTHS) regression testing.

5. Environmental Sustainability: The material is 100% recyclable, contains no heavy metals or plasticizers, and the coil format minimizes material waste during installation. Carbon black stabilization ensures UV resistance without leaching concerns.

Storage & Handling Guidelines