Repellent coating composition and coating, method for making and uses thereof
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Solution Overview
Problem
Existing coating systems lack sufficient abrasion and chemical resistance, leading to degradation of repellent surfaces and increased maintenance needs due to fouling and scaling issues, which affect the efficiency and longevity of structural surfaces.
Innovation Solution
A cross-linkable coating composition comprising silanes with thiourethane or urea linkages and polydimethylsiloxane as a low surface energy additive, providing a chemically and mechanically stable repellent surface that resists fouling and scaling through a chemically cross-linked 3D network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluoropolymers or polydimethylsiloxane are used to obtain low surface energy and hydrophobicity, then repellent properties are improved, but scratch resistance and adhesion deteriorate
Solution Approach 1:
The invention combines polydimethylsiloxane (providing low surface energy and hydrophobicity) with silane coating materials containing perfluoroalkyl moieties (providing scratch and abrasion resistance). This composite coating system resolves the contradiction by integrating materials with complementary properties, where each component contributes its strengths to the overall coating performance.
Solution Approach 2:
The invention modifies the chemical composition and structure of the coating by incorporating specific silane compounds with perfluoroalkyl groups, changing the physical and chemical parameters of the coating surface. This allows simultaneous achievement of low surface energy (for repellency) and enhanced mechanical durability (for scratch resistance).
2Strength
If silane coating materials comprising perfluoroalkyl moieties are used to improve scratch resistance and adhesion, then mechanical durability is improved, but abrasion resistance of repellent properties deteriorates
Solution Approach 1:
The coating system uses a composite formulation where polydimethylsiloxane provides the repellent surface with low surface energy, while silane materials with perfluoroalkyl moieties provide the mechanical backbone for scratch and abrasion resistance. The synergistic interaction between these components ensures both mechanical durability and sustained repellent properties under abrasion.
Solution Approach 2:
The invention merges two previously separate coating systems into a single integrated coating: the polydimethylsiloxane-based hydrophobic coating and the silane-based mechanically durable coating. This unified system achieves both low surface energy and high mechanical resistance simultaneously, resolving the contradiction between scratch resistance and repellent property durability.
3Reliability
If conventional coating systems are applied to prevent fouling, then initial repellent properties are achieved, but long-term stability under mechanical and chemical attacks deteriorates
Solution Approach 1:
The invention creates a composite coating system that combines the fouling-prevention capabilities of polydimethylsiloxane with the mechanical and chemical durability of cross-linked silane networks. This composite structure maintains repellent properties over extended periods by protecting the low surface energy component from degradation through mechanical and chemical exposure.
Solution Approach 2:
The coating design provides different functional zones: the polydimethylsiloxane component creates a low surface energy outer layer for fouling prevention, while the silane-based cross-linked network provides a mechanically robust underlying structure. This local differentiation of material properties ensures both initial repellency and long-term stability under various attack conditions.
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 composition achieves long-term robustness and easy cleaning, reducing maintenance needs and fouling by maintaining repellent properties under mechanical and chemical attacks, with a 60-70% reduction in fouling on heat exchanger plates after four months of exposure to crude oil.
Implementation Method 1
A repellent surface, also called Easy-To-Clean surface, is a surface providing a low surface energy leading to hydrophobicity defined by the surface providing a static water contact angle above 90° and possibly additionally leading to oleophobicity
Implementation Method 2
wherein said silanes are optionally partly or completely hydrolysed and optionally condensed
Implementation Method 3
wherein said silanes are optionally partly or completely hydrolysed and optionally condensed
Implementation Method 4
a polypodal silane having at least one urea or thiourethane linkage between the at least two Si atoms present in the silane molecule
Data Source
AI summary
This invention relates to a cross-linkable coating composition comprising: (i) one or more silanes comprising either of the following two options: - at least three hydrolysable groups or - at least two hydrolysable groups and at least one organofunctional group capable of forming chemical bonds upon curing, and (i.a) the sum of said silanes constitutes at least 20 % of the total mass of the coating compositions combined solids and silanes, and (i.b) said silanes are possibly partly or completely hydrolysed and possibly partly condensed; and (ii) at least one low surface energy additive, wherein (ii.a) said low surface energy additive comprises polydimethylsiloxane chemically bonded to at least one functional group, (ii.b) said functional group is configured for the polydimethylsiloxane moiety to cross-link with said coating composition, (ii.c) said polydimethylsiloxane constitutes 0.01 % to 15 % of the mass of said cured coating, when said coating composition is cured, (ii.d) said polydimethylsiloxane moiety has a molecular weight of more than 1600 g/mol.