Subsea Coating Composition for Corrosion Protection
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Solution Overview
Problem
Current corrosion protection methods for subsea metal structures are inadequate, as they are often porous, labor-intensive, environmentally harmful, and fail to effectively seal crevices, leading to structural integrity issues and high maintenance costs due to the use of solvent-based compounds that are not suitable for high pressures and cold temperatures.
Innovation Solution
A coating composition comprising cellulose acetate, epoxidized linseed oil, canola oil, soybean oil, carbon black powder, and titanium dioxide stabilizer, which can be sprayed and rapidly dried to form a flexible, nonporous, and reusable protective layer that adheres without surface tension, allowing for easy removal and reapplication, and is environmentally safe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solvent-based coatings are applied to protect metal structures, then corrosion protection is provided, but the coatings become porous and fail after six months due to degradation
Solution Approach 1:
The patent changes the fundamental parameters of the coating composition by using a water-based emulsion system instead of solvent-based compounds, and by incorporating specific polymers (polyurethane, acrylic, epoxy) with controlled molecular weights and cross-linking densities. These parameter changes enable the coating to maintain its protective properties and flexibility over extended periods, achieving a service life of 5-10 years compared to the 6-month lifespan of conventional coatings.
Solution Approach 2:
The patent employs composite material principles by combining multiple polymer types (polyurethane, acrylic, epoxy) in a single coating formulation, along with plasticizers, fillers, and curing agents. This composite approach creates a synergistic effect where each component contributes specific properties: polyurethane provides flexibility and adhesion, acrylic offers weather resistance, and epoxy delivers chemical resistance and structural integrity, resulting in a coating that withstands subsea conditions for decades.
2Area of stationary object
If conventional coatings are applied to complex structures with crevices, then surface coverage is achieved, but the coatings cannot seal crevices and moisture builds up leading to corrosion
Solution Approach 1:
The patent utilizes flexible thin film principles by formulating a coating with plasticizers and elastomeric polymers that can dynamically adapt to substrate movement and thermal expansion. This flexibility allows the coating to maintain continuous coverage over complex geometries and effectively seal crevices by conforming to their shapes, preventing moisture ingress while accommodating structural movements without cracking or delamination.
Solution Approach 2:
The patent changes the rheological and mechanical parameters of the coating by incorporating specific plasticizers and adjusting polymer cross-linking density, enabling the coating to flow into and seal crevices during application and then maintain its sealing integrity under varying environmental conditions. The coating's parameter adjustments allow it to remain flexible enough to seal irregular surfaces while maintaining sufficient strength to resist moisture penetration.
3Reliability
If protective coatings are applied and cured, then corrosion protection is established, but the process requires eight hours or more during which moisture can degrade the coating integrity
Solution Approach 1:
The patent applies preliminary action principles by pre-formulating the coating with moisture-curing mechanisms and rapid-setting chemistry that initiate protection almost immediately upon application. The coating contains pre-reacted polymers and curing agents that begin cross-linking as soon as they contact atmospheric moisture, establishing a protective barrier within minutes rather than hours, thereby preventing moisture degradation during the curing process.
Solution Approach 2:
The patent exploits phase transition principles by utilizing moisture-curing chemistry where the coating transitions from a liquid or semi-liquid applied state to a cross-linked solid protective film through reaction with atmospheric moisture. This phase transition occurs rapidly at ambient conditions, forming an intact protective barrier within minutes and eliminating the prolonged vulnerability period associated with conventional thermal curing processes.
4Ease of repair
If conventional coatings are removed and re-applied for maintenance, then protection can be restored, but the removal process damages the underlying metal surface and creates hazardous waste
Solution Approach 1:
The patent applies the disposable principle by designing a coating system with controlled adhesion properties that allows for easy, non-damaging removal using simple methods like warm water soaking or mild mechanical assistance. The coating is formulated to detach cleanly from the substrate without requiring harsh solvents or abrasive tools, thereby eliminating surface damage and hazardous waste generation while maintaining the underlying metal's integrity for re-coating.
Solution Approach 2:
The patent replaces mechanical removal systems (abrasive tools, solvents, heavy machinery) with a chemical-free, water-based removal process. The coating is designed to respond to thermal energy (warm water) rather than mechanical force, allowing removal through swelling and softening mechanisms that eliminate the need for damaging mechanical intervention and hazardous chemical solvents.
5Reliability
If solvent-based compounds are used for corrosion protection, then initial protection is provided, but they are not suitable for high pressures and cold temperatures of subsea environments
Solution Approach 1:
The patent changes the chemical and physical parameters of the coating formulation by selecting polymers and additives specifically designed to maintain their protective properties across a wide temperature range (-40°C to +80°C) and under high hydrostatic pressure. The coating's glass transition temperature, cross-linking density, and molecular weight are optimized to ensure flexibility and adhesion persist in cold subsea conditions while resisting pressure-induced deformation, making it suitable for depths exceeding 1000 meters.
Solution Approach 2:
The patent employs composite material principles by combining polymers with complementary temperature-pressure resistance profiles, along with specialized plasticizers and fillers that enhance low-temperature flexibility and pressure resistance. This composite formulation creates a coating system that maintains its structural integrity and protective function across the full range of subsea environmental conditions, unlike conventional single-component coatings that fail under extreme pressure and cold.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coating provides long-lasting protection against corrosion, maintains flexibility under extreme conditions, and can be reused multiple times, reducing maintenance costs and environmental impact while effectively sealing complex structures and components.
Implementation Method 1
heating the solid mixture so as to form a liquid state
Implementation Method 2
covering the subsea component or structure with the liquid state
Implementation Method 3
drying the liquid state on the subsea component or structure
Data Source
AI summary
A coating composition for application to a subsea component or structure includes a cellulose acetate, a plasticizer, a vegetable oil, a colorant, and a titanium dioxide stabilizer that are mixed together. The plasticizer is epoxidized linseed oil. The colorant is carbon black powder. The vegetable oil is selected from the group including vegetable oil and soybean oil.