3LPP Heat Shrink Wrap Around Sleeve Cross-Linked PP Backing High Temperature Pipeline Joint Coating ISO 21809-3

3LPP Heat Shrink Wrap Around Sleeve for High Temperature Pipeline Joint Corrosion Protection

Product Overview

The CNP-SGL-3LPP-HT is a patented, internationally leading three-layer polypropylene (3LPP) heat shrink wrap around sleeve system engineered for field-applied corrosion protection of welded pipe joints in high-temperature oil, gas, and water pipelines. Fully compliant with ISO 21809-3:2016, this system is optimized for the extreme operating conditions of Middle Eastern oil and gas pipelines and offshore marine environments, with continuous service capability exceeding 110C.

Construction & Layer Structure

The 3LPP system replicates the performance of factory-applied three-layer polypropylene coatings through a precisely engineered three-layer structure:

• Layer 1 – High Tg Epoxy Primer: A two-component, solvent-free modified epoxy with glass transition temperature (Tg) ≥ 120C, providing exceptional adhesion to grit-blasted steel (Sa 2.5). This high-temperature resistant primer forms a robust anti-corrosion foundation and ensures strong interlayer bonding.
• Layer 2 – PP Hotmelt Adhesive: A specially formulated polypropylene-based copolymer adhesive that creates a permanent fusion bond between the epoxy primer and the PP backing. The adhesive maintains integrity and peel strength even at continuous operating temperatures up to 120C, with measured peel strength of ≥4.5 N/mm at 110C.
• Layer 3 – Radiation Cross-Linked PP Backing: The outer layer utilizes radiation cross-linked polypropylene technology cured under electron beam to achieve superior mechanical strength, UV stability, and chemical resistance. This advanced backing provides a robust barrier against mechanical damage, soil stress, and harsh environmental factors typical of desert and marine installations.

Key Features & Benefits

• High Temperature Performance: Continuous operating temperature up to 120C, specifically designed for high-temperature crude oil and gas transmission lines in the Middle East.
• Superior Peel Strength: Delivers 27 N/mm peel strength at 23C and 4.5 N/mm at 110C (ASTM D1000), ensuring reliable long-term adhesion under thermal cycling conditions.
• Marine Environment Resistant: Excellent resistance to salt spray, humidity, and marine atmospheric corrosion, making it ideal for offshore platforms and coastal pipeline installations.
• Rapid Installation: Using a medium frequency induction heater, each joint is completed in just 5 minutes per set, significantly reducing field construction time and labor costs.
• Radiation Cross-Linked PP Technology: Patented international-leading cross-linking process enhances backing dimensional stability, impact resistance, and long-term ageing performance compared to standard PE-based sleeves.
• ISO 21809-3:2016 Certified: Independently tested and qualified to the latest international standard for field joint coating of pipelines.
• Cathodic Disbondment Resistance: Minimal CD at elevated temperatures, ensuring compatibility with impressed current cathodic protection systems.

Technical Specifications

Applications

• High-temperature crude oil transmission pipelines (Middle East onshore)
• Natural gas trunk lines operating above 80C
• Offshore and subsea pipeline riser joints
• Directional drilling and horizontal directional drilling entry/exit points
• Field repair of factory-applied 3LPP coatings
• Water injection and produced water pipelines

Epoxy Primer System

The CNP-P-HT two-component high Tg epoxy primer is specifically formulated for compatibility with the 3LPP system. With a glass transition temperature exceeding 120C, it maintains adhesion integrity throughout the full operating temperature range. The primer is applied directly to the cleaned weld joint area using foam rollers prior to sleeve installation, providing an additional barrier layer and ensuring maximum peel strength between the steel substrate and the PP adhesive.

Packaging & Availability

Available widths from 300mm to 600mm and thicknesses of 2.5mm, 3.0mm, and 3.5mm to accommodate pipe diameters from 200mm to 1800mm. Supplied in standard export-grade wooden cases with moisture-proof lining. Custom dimensions and bulk roll configurations available upon request.