Breakthrough: LFT-G® PA6 LGF as Intermediate Reinforcement Layer in 3-Layer Co-extruded Corrugated Pipes
As performance requirements for piping systems in new energy vehicles, energy storage systems, and industrial fluid transport continue to rise, multi-layer co-extruded composite pipe technology is emerging as a key industry focus. Three-layer co-extruded composite pipes - consisting of an inner layer, an intermediate reinforcement layer, and an outer layer - are manufactured by co-extruding different functional materials in a single pass, delivering a comprehensive performance profile that no single material can offer.
In this technical approach, the selection of the intermediate reinforcement layer is critical. Traditionally, the intermediate layer has served primarily as a bonding layer, contributing little to mechanical performance. However, the latest application case from LFT-G® demonstrates that PA6 LGF (long glass fiber-reinforced polyamide 6) as an intermediate-layer reinforcement masterbatch is redefining the performance boundaries of 3-layer co-extruded composite pipes.
Technical Breakthrough: Long Fiber Reinforcement Enters Pipe Extrusion
LFT-G® PA6 LGF is a high-performance thermoplastic composite based on a polyamide 6 matrix reinforced with long glass fibers (LGF). Unlike conventional short-fiber reinforced materials, LFT-G® employs a proprietary pultrusion process that fully impregnates continuous glass fibers with PA6 resin before pelletizing, producing long-fiber reinforced pellets with a fiber length of 10–12 mm.
When PA6 LGF is applied as an intermediate reinforcement layer masterbatch in 3-layer co-extruded composite pipes, the long fibers form a three-dimensionally oriented reinforcing network along the pipe's axial direction during extrusion, delivering three core advantages:
- Significantly improved ring stiffness and pressure resistance - the long fiber network effectively bears circumferential stress, substantially enhancing the pipe's deformation resistance under buried and high-pressure conditions
- Dramatically enhanced impact and crack resistance - long fibers form a bridging structure within the matrix that effectively arrests crack propagation
- Excellent dimensional stability and creep resistance - long fiber reinforcement significantly reduces creep deformation under long-term loading
The breakthrough: By introducing LFT-G® PA6 LGF into the intermediate layer, pipe manufacturers can achieve 30–50% higher ring stiffness and 2–3× higher impact resistance compared to conventional non-reinforced or short-fiber reinforced layers - without changing the existing co-extrusion process.
Typical Structure of 3-Layer Co-extruded Composite Pipes
In 3-layer co-extruded composite pipes, each layer has a distinct functional role:
| Layer | Function | Recommended Material |
|---|---|---|
| Outer Layer | Weather resistance, flame retardance, abrasion resistance | High-viscosity, low-melting polyamide resin |
| Intermediate Layer (Reinforcement) | Bear circumferential stress, enhance ring stiffness | LFT-G® PA6 LGF (long glass fiber reinforced masterbatch) |
| Inner Layer | Chemical resistance, low friction | High-viscosity block copolymer polypropylene |
With the introduction of LFT-G® PA6 LGF into the intermediate layer, pipe ring stiffness can be improved by 30–50%, impact resistance by 2–3×, while maintaining excellent low-temperature toughness and heat-aging resistance.
Applications
3-layer co-extruded composite pipes incorporating PA6 LGF reinforcement in the intermediate layer are suitable for both straight pipes and corrugated pipes, covering a wide range of industrial and infrastructure applications:
- Chemical pipelines - excellent chemical resistance and long-term durability in corrosive media transport
- Water supply systems - high ring stiffness ensures reliable performance under pressure and soil loading
- Drainage systems - impact resistance and dimensional stability for underground installation
- Industrial piping - withstands mechanical stress, vibration, and temperature fluctuations
- Sewerage pipelines - superior creep resistance and corrosion protection for demanding wastewater environments
- Corrosion-resistant piping - PA6 LGF reinforcement provides structural integrity while the multi-layer design delivers chemical barrier properties
Market Trend: Demand for Multi-Layer Nylon Composite Pipes Continues to Grow
As new energy vehicle penetration continues to rise, the use of multi-layer nylon composite pipes in automotive applications is accelerating. The three-layer straight pipe/corrugated pipe (PA/TIE/PP) solution for cooling systems represents the current mainstream development direction, with significant market potential. The development of multi-layer co-extrusion technology offers substantial opportunities for improving pipe physical properties and cost optimization.
The introduction of LFT-G® PA6 LGF reinforcement masterbatch provides the industry with a high-performance, scalable solution for the intermediate reinforcement layer of 3-layer co-extruded composite pipes - not only significantly enhancing pipe mechanical performance, but also offering pipe manufacturers a convenient path to product upgrade without changing their existing co-extrusion process.
LFT-G® PA6 LGF is not just a reinforcement material - it is a process-compatible upgrade that turns the intermediate layer of a composite pipe from a passive bonding layer into an active load-bearing structural layer, delivering measurable performance gains with minimal process change.
Contact the LFT-G® technical team
Xiamen LFT Composite Plastic Co., Ltd is a global supplier of long fiber reinforced thermoplastics with 20+ years of innovation. We specialize in LFT‑PP, LFT‑PA, LFT‑PPS, and LFT‑Elastomers – offering high‑strength, lightweight alternatives to metal for automotive, aerospace, and industrial applications.
