3LPP Hybrid Heat Shrink Sleeve Combines A polypropylene Backing with A thermoplastic Hybrid Adhesive

Polypropylene Backing + Thermoplastic Hybrid Adhesive | Superior Bonding to PP, PE & FBE Coatings

Our 3LPP Hybrid Coating System Heat Shrink Sleeve is an advanced heat-shrinkable field joint coating that combines a polypropylene backing with a thermoplastic hybrid adhesive. This innovative combination delivers the mechanical protection of polypropylene with the ease of installation of a traditional adhesive system—allowing for lower preheat temperatures and faster application than conventional 3LPP systems.

The system is designed for a three-layer field joint coating configuration on polypropylene-coated pipelines, as well as a three-layer bend coating. The adhesive has been formulated to bond directly to the mainline coating, while epoxy is applied to the steel only. This hybrid approach provides superior bonding to PP, PE, and FBE coatings without the high preheat and long application times associated with traditional 3LPP systems.

The epoxy is applied only to the steel cutback, while the hybrid adhesive bonds to the adjacent plant coating. This is the key distinction from conventional 3LPP systems, where the adhesive must bond to both steel and plant coating.

Values are indicative and shall be confirmed against the specific CNPetro product data sheet.

ISO 21809-3 specifies requirements for field joint coatings on buried and submerged pipelines. Polypropylene-backed heat-shrinkable systems fall under Type 14D classifications, with performance requirements based on the maximum design temperature and system construction. The hybrid system is designed to meet the applicable Type 14D classification requirements, including peel strength, cathodic disbondment resistance, impact resistance, indentation resistance, and thermal ageing.

Surface Preparation: Abrasive blast clean the steel cutback to Sa 2½ per ISO 8501-1; clean and roughen the adjacent plant coating overlap zone.

Preheat: Preheat the steel surface to the manufacturer's recommended temperature (lower than conventional 3LPP systems).

Apply Epoxy Primer: Mix two-component epoxy and apply to the steel cutback only.

Position Sleeve: Wrap the heat-shrinkable sleeve around the joint, centering over the weld with equal overlap onto the plant coating (PP, PE, or FBE).

Apply Closure Patch: Secure the closure patch along the overlap.

Shrink: Apply heat uniformly with a propane torch, working from the center outward, until the backing shrinks and adhesive flows at the edges.

Inspect: Verify complete shrinkage, adhesive flow, and absence of voids or lifted edges.

CNPetro — Protecting pipelines. Advancing performance.

For product data sheets, ISO 21809-3 qualification documentation, or technical consultation, please contact our sales team.

Keywords: 3LPP hybrid coating system, heat shrink sleeve, polypropylene backing, thermoplastic hybrid adhesive, lower preheat temperature, PP/PE/FBE bonding, field joint coating, three-layer bend coating, ISO 21809-3

Application Cases of 3LPP Coating System Heat Shrink Sleeve

Umm Lulu Offshore Project, UAE Subsea oil & gas trunk line, total ~150 km, 6”–20” OD. 3LPP HSS sleeves for field joints of 3LPP coated line pipe. Designed for lay-barge roller load, seawater corrosion and high operating temperature, with fast cooling cycle for offshore construction.

Halfaya & Badra Onshore Oilfields, Iraq High-temperature crude oil flowlines, up to 105°C service temp, H₂S & chloride contaminated soil, desert abrasion. 3LPP sleeves used for buried girth welds & HDD crossings.

Chad Crude Oil Export Pipeline, Central Africa 23.8 km high-temperature section above 80°C, tropical aggressive soil.  3LPP sleeve system selected instead of 3LPE due to superior heat resistance.

Algeria–Spain Cross-Border Gas Pipeline 50 km multi-environment pipeline (onshore, shallow water & deep water). 2.5mm standard , 6mm heavy-duty HSS for deepwater mechanical protection.

Offshore & HDD Projects in China Offshore Waters Subsea injection lines, production pipelines, river/channel HDD crossings. Compliant with ISO 21809-3 and DNV-RP-F102 for field joint coating.