Multi-Layer Coating System for Aquatic Biofouling Control
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Solution Overview
Problem
Existing foul release coatings based on polysiloxane resins face contamination issues, poor adhesion, and aesthetic problems when applied to surfaces contaminated with polysiloxane, and they do not provide adequate mechanical properties compared to non-polysiloxane coatings.
Innovation Solution
A multi-layer coating system comprising a primer layer, a tie-coat layer with a binder polymer obtained from copolymerizing ethylenically unsaturated monomers with curable alkoxysilyl functional groups, and a non-aqueous foul release topcoat layer with a curable polymer having an organic backbone and terminal or pendant alkoxysilyl groups, but without polysiloxane, ensuring good adhesion and mechanical properties while preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polysiloxane-based foul release coatings are applied to provide excellent foul release properties, then fouling resistance is improved, but adhesion to contaminated surfaces deteriorates and contamination issues arise
Solution Approach 1:
The coating system is divided into multiple layers: a primer layer for substrate preparation, a tie-coat layer with binder polymer containing curable alkoxysilyl groups for adhesion promotion, and a foul release topcoat layer. This segmentation allows each layer to perform its specific function without interfering with others, solving the adhesion-contamination contradiction.
Solution Approach 2:
The tie-coat layer acts as an intermediary between the substrate and the polysiloxane-based topcoat. It contains binder polymers with curable alkoxysilyl groups that form strong bonds with both the substrate and the topcoat, preventing contamination issues while maintaining excellent adhesion.
2Reliability
If polysiloxane resins are used to achieve good foul release properties, then fouling resistance is improved, but mechanical properties deteriorate
Solution Approach 1:
The tie-coat layer uses composite materials combining binder polymers with curable alkoxysilyl groups, creating an organic-inorganic hybrid network. This composite structure provides both strong mechanical properties and excellent adhesion to the polysiloxane topcoat.
3Reliability
If polysiloxane-based coatings are applied to provide fouling resistance, then foul release properties are improved, but aesthetic appearance deteriorates due to pin hole and fish eye effects
Solution Approach 1:
The primer and tie-coat layers are applied beforehand to create a perfectly prepared surface. This preliminary action ensures that the final polysiloxane topcoat is applied to a contamination-free, properly conditioned surface, preventing pin hole and fish eye effects and ensuring excellent aesthetic appearance.
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 multi-layer coating system provides excellent foul release and ice-release properties, improved mechanical properties like abrasion resistance, and allows for easy application on contaminated surfaces without adhesion or aesthetic issues, making it suitable for aquatic environments.
Implementation Method 1
The polyurethane and the polysiloxane self-crosslink to form an organic-inorganic hybrid network
Implementation Method 2
a curable polymer having an organic backbone with terminal and/or pendant alkoxysilyl groups
Implementation Method 3
polysiloxane forms a surface structure with low surface energy that provides foul release properties
Data Source
AI summary
The embodiments herein relate to a substrate coated with a multi-layer coating system including: optionally a primer layer applied to the substrate and deposited from a primer coating composition; a tie-coat layer applied to the substrate or to the optional primer layer, deposited from a tie-coat composition including a binder polymer obtainable by copolymerizing a mixture of ethylenically unsaturated monomers, the binder polymer having curable alkoxysilyl functional groups. The substrate can include a topcoat layer applied to the tie-coat layer, and deposited from a non-aqueous liquid foul release coating composition including a curable resin system including i) a curable polymer and optionally ii) a curing agent and/or a catalyst, where the non-aqueous liquid foul release coating composition is essentially free of a curable polysiloxane.