Tie-Coat Composition for Silane Topcoats
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Solution Overview
Problem
There is a need for tie-coat compositions that exhibit improved adhesion to foul release topcoats based on resins with condensable silane groups, such as polysiloxane resins or silane terminated polyurethanes or polyesters.
Innovation Solution
A tie-coat composition comprising one or more binder polymers obtainable by copolymerizing a mixture of ethylenically unsaturated monomers, with pendant curable alkoxysilyl functional groups. These binder polymers have a specific structure with a hydrocarbon linker group and a heteroatom, providing excellent adhesion to topcoats with condensable silane groups without the use of a crosslinking agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional tie-coat compositions are used, then the coating system can be applied, but adhesion to foul release topcoats based on resins with condensable silane groups is insufficient
Solution Approach 1:
The invention changes the chemical parameters of the tie-coat composition by incorporating binder polymers with specific pendant curable alkoxysilyl functional groups that have different reactivity and bonding characteristics. This allows the tie-coat to form strong chemical bonds with both the substrate and the polysiloxane-based topcoat, resolving the adhesion problem.
Solution Approach 2:
The invention uses a composite binder polymer system combining ethylenically unsaturated monomers with pendant curable alkoxysilyl functional groups. This composite structure provides both mechanical bonding capability and chemical reactivity toward silane groups in the topcoat, achieving superior adhesion performance.
2Reliability
If polysiloxane-based resins are used in topcoats, then fouling resistance is achieved, but bonding to the tie-coat layer becomes difficult
Solution Approach 1:
The tie-coat composition acts as an intermediary layer between the substrate and the polysiloxane topcoat. The binder polymers with pendant curable alkoxysilyl functional groups provide chemical bridges that bond to both the substrate and the silane groups in the polysiloxane topcoat, enabling strong interlayer adhesion while maintaining fouling resistance.
Solution Approach 2:
The invention modifies the chemical reactivity parameters of the tie-coat by using binder polymers with curable alkoxysilyl groups that can undergo condensation reactions with the polysiloxane topcoat. This chemical parameter change enables strong bonding without compromising the fouling release properties of the polysiloxane resin.
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 tie-coat composition achieves very good dry adhesion, freshwater adhesion, and saltwater adhesion to topcoats, making it particularly suitable for use in combination with foul release coating compositions.
Implementation Method 1
pendant curable alkoxysilyl functional groups... providing excellent adhesion to topcoats with condensable silane groups
Data Source
AI summary
The present disclosure relates to a tie-coat composition comprising one or more binder polymers obtainable by copolymerizing a mixture of ethylenically unsaturated monomers, wherein the tie-coat composition provides a tie-coat with good dry adhesion, freshwater adhesion and saltwater adhesion to topcoats based on resins with condensable silane groups such as polydiorganosiloxane resins with hydrolysable groups or organic resins with terminal and/or pendant alkoxysilyl groups. The present disclosure further relates to a process for controlling aquatic fouling on a surface of a man-made object comprising applying such tie-coat composition and a topcoat composition, and to a substrate coated with a tie-coat layer deposited from such tie-coat composition and a topcoat layer.