Propylene-Based Composition for Underwater Joint Bonding
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Solution Overview
Problem
Existing pipe coatings and field joint coatings for underwater pipelines face challenges in providing effective corrosion protection and mechanical strength under hydrostatic pressure, particularly when applied in the field before installation.
Innovation Solution
A polyolefin composition comprising specific ratios of heterophasic polyolefin polymers, including crystalline propylene homopolymers and ethylene α-olefin copolymers, is used to create a field joint coating that enhances bonding with factory-applied coatings and improves mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pipe coatings and field joint coatings are used for underwater pipelines, then the pipes can be protected from seawater corrosion, but the coatings may not provide sufficient mechanical strength and bonding performance under hydrostatic pressure
Solution Approach 1:
The patent uses a composite material system consisting of a polyolefin composition (containing polypropylene and polyethylene components) combined with a reactive diluent (epoxy or vinyl ester based). This composite formulation creates a field joint coating that achieves both corrosion protection and enhanced mechanical strength under hydrostatic pressure, resolving the contradiction between reliability and strength.
2Ease of manufacture
If field joint coating is applied before pipe installation, then the coating can bond with factory applied pipe coating, but the coating must withstand hydrostatic pressure and mechanical stresses
Solution Approach 1:
The patent modifies the chemical composition parameters of the field joint coating by incorporating specific ratios of polyolefin components and reactive diluents. This parameter change enables the coating to achieve both good bonding with factory applied coatings and sufficient durability under hydrostatic pressure, resolving the contradiction between ease of manufacture and reliability.
Data Source
AI summary
A polyolefin composition made from or containing a first heterophasic polyolefin polymer A) made from or containing a first crystalline propylene homopolymer matrix, a first propylene ethylene copolymer having an ethylene content ranging from 20.0 wt % up to 35.0 wt %, a second propylene ethylene copolymer having an ethylene content ranging from 55.0 wt % up to 70.0 wt %, and a second heterophasic polyolefin polymer B) made from or containing a second crystalline propylene homopolymer matrix, an ethylene C4-C10 α-olefin copolymer having an ethylene content ranging from 65.0 wt % up to 85.0 wt %, and a third propylene ethylene copolymer having an ethylene content ranging from 40.0 wt % up to 50.0 wt %.