Chromium-Free Epoxy Primer for Ship Propeller Adhesion
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Solution Overview
Problem
Existing primer coatings for ship propellers, particularly those made of nonferrous metals and stainless steel, face challenges with adhesion and hardness, especially at low temperatures, and contain carcinogenic chromium compounds.
Innovation Solution
A chromium compound-free coating composition comprising epoxy resin, an amine curing agent, a silane coupling agent, water, and a pigment, with specific ratios and types of components to enhance adhesion and hardness, and a method for forming a layered antifouling coating film using a silicone resin antifouling coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional etching primer containing zinc chromate is used to form a primer layer, then adhesion between the propeller and antifouling coating film is enhanced through oxidation of zinc chromate, but the coating contains carcinogenic chromium compounds that pose health risks
Solution Approach 1:
The invention extracts and removes the harmful zinc chromate component from the primer formulation while retaining the essential adhesion function through alternative ingredients such as epoxy resin and silane coupling agents, thereby eliminating carcinogenicity while maintaining bonding strength
Solution Approach 2:
The invention employs a composite primer system combining epoxy resin, silane coupling agent, and other functional ingredients that work synergistically to provide adhesion without relying on chromium compounds, replacing the single-component zinc chromate system with a multi-functional composite formulation
2Use of energy by stationary object
If the primer is dried at low temperature (e.g., 5°C) to preserve the propeller, then energy consumption is reduced, but the coating film exhibits insufficient drying property and inadequate hardness
Solution Approach 1:
The invention modifies the chemical composition parameters of the primer, specifically incorporating silane coupling agents and adjusting the epoxy resin formulation, which enables the coating to achieve adequate hardness and curing at low temperatures without requiring high energy input for drying
Solution Approach 2:
The silane coupling agent undergoes hydrolysis and condensation reactions at low temperatures, facilitating phase transition from liquid to gel state, which enables proper film formation and hardening of the coating even at 5°C without requiring external heating
3Strength
If a primer coating is applied to nonferrous metals and stainless steel to improve adhesion, then the antifouling coating adheres better to the propeller, but the oxide films on metal surfaces create low surface activity that hinders firm adhesion
Solution Approach 1:
The silane coupling agent acts as an intermediary between the metal oxide surface and the epoxy resin matrix, forming chemical bonds with both the metal oxide and the organic polymer, thereby bridging the interface and enabling firm adhesion despite the low surface activity of oxidized metal surfaces
Solution Approach 2:
The invention changes the chemical parameters of the primer formulation by incorporating silane coupling agents that can chemically interact with metal oxide surfaces, transforming the passive oxide interface into an active bonding surface that enhances adhesion without requiring surface treatment
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 excellent adhesion and hardness on nonferrous metals and stainless steel substrates even at low temperatures, providing long-term anticorrosion and antifouling properties without using chromium compounds, thus ensuring better safety and environmental sustainability.
Implementation Method 1
a silane coupling agent (C)... enabling the formation of a coating film having excellent adhesion to a substrate
Implementation Method 2
an amine curing agent (B)... enabling the formation of a coating film having excellent adhesion to a substrate
Implementation Method 3
water (D)... a content of the water (D) is 3.5 to 11 parts by weight with respect to 100 parts by weight (of non-volatile content)
Data Source
AI summary
The present invention relates to a coating composition, a primer coating film, a layered antifouling coating film, a method of producing a substrate with a primer coating film, and a method of producing a substrate with a layered antifouling coating film. The coating composition includes an epoxy resin (A), an amine curing agent (B), a silane coupling agent (C), water (D), and a pigment (E). In the coating composition, the content of the water (D) is 3.5 to 11 parts by weight with respect to 100 parts by weight of non-volatile content in the coating composition, and a pigment volume concentration of the coating composition is 37 to 47%.