Silane-Terminated Polyurethane Marine Coating Adhesion
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Solution Overview
Problem
Traditional fouling release coatings for marine surfaces require multiple layers due to adhesion issues between polysiloxane top coats and epoxy primers, leading to increased application time and cost, and existing solutions do not adequately address the need for improved adhesion and corrosion resistance.
Innovation Solution
A multilayer fouling release coating system comprising a curable or crosslinkable polysiloxane and a silane terminated polyurethane, which improves adhesion properties, allowing for the potential elimination of intermediate layers and direct application over existing coatings without the need for a link coat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polysiloxane fouling release top coat is applied directly over an epoxy primer, then adhesion between layers is poor, but using intermediate link coats and tie coats increases the number of layers required
Solution Approach 1:
The patent introduces a silane-terminated polyurethane polymer as an intermediary substance that chemically bonds to both the epoxy primer and the polysiloxane top coat. This mediator polymer contains epoxide groups that react with the primer and silane groups that react with the polysiloxane, creating strong interlayer adhesion and eliminating the need for separate link and tie coats.
Solution Approach 2:
The patent creates a composite coating system where the polyurethane polymer acts as a hybrid layer combining organic (epoxide) and inorganic (silane) functional groups. This composite approach allows the single intermediate layer to perform multiple functions: bonding to epoxy, bonding to polysiloxane, and providing corrosion resistance.
2Reliability
If multiple intermediate layers (link coat and tie coat) are used to improve adhesion, then coating reliability improves, but application time and cost increase
Solution Approach 1:
The patent merges the functions of the link coat and tie coat into a single polyurethane polymer layer. This consolidated approach maintains the protective and adhesive functions of both intermediate layers while reducing the number of application steps, drying times, and overall processing time.
Solution Approach 2:
The silane-terminated polyurethane polymer is designed to perform multiple functions simultaneously: it provides adhesion to epoxy primers, adhesion to polysiloxane top coats, and corrosion resistance. This multi-functional polymer eliminates the need for specialized separate layers for each function.
3Reliability
If traditional multilayer coating systems are used, then corrosion resistance is maintained, but the number of layers and application complexity increase
Solution Approach 1:
The patent changes the chemical parameters of the intermediate layer by using a polyurethane polymer with specific functional groups (epoxide and silane) that enable reactions with both adjacent layers. This parameter change allows a single layer to provide the corrosion resistance and adhesion properties previously requiring multiple layers.
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 system enhances adhesion, reduces the number of layers required, and provides improved corrosion resistance, enabling cost-effective and time-efficient application while maintaining effective fouling release performance.
Implementation Method 1
The introduction of the polyurethane improves the adhesive properties of the polysiloxane coating layer formulation, thereby allowing the formation of an effective fouling release coating system with fewer layers than those currently use in the art.
Implementation Method 2
A multilayer fouling release coating comprising a coating composition for use as a layer with improved adhesion properties comprising a polysiloxane and a silane terminated polyurethane.
Implementation Method 3
The tie coat as well as the top coat of a fouling release coating are conventionally based on a three component system of a polymer, crosslinker and catalyst. When combined, these three components cure simply in the presence of the moisture in the air.
Implementation Method 4
When combined, these three components cure simply in the presence of the moisture in the air. This curing process produces an elastomeric type coating on the surface.
Implementation Method 5
Low surface energy, low glass transition temperature (Tg) and low elastic modulus of the surface makes it difficult for the organisms to adhere firmly to the surface, which reduce the accumulation of marine organisms.
Implementation Method 6
Low surface energy, low glass transition temperature (Tg) and low elastic modulus of the surface makes it difficult for the organisms to adhere firmly to the surface.
Implementation Method 7
When the water moves relative to the surface, the forces generated remove the attached fouling organisms from the surface. Thus, to be used successfully, the hydrodynamic forces on the coated surface have to be sufficiently high for effective release of the fouling organisms.
Data Source
AI summary
A composition for use in the manufacture of a fouling release coating, e.g. at least one layer of a fouling release coating, comprising at least one curable or crosslinkable polysiloxane and at least one silane terminated polyurethane.