Antifouling Coating Film Thickness Control via Color Difference

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Solution Overview

Problem

Existing methods for forming antifouling coating films on large underwater structures, such as marine vessels, face challenges in achieving uniformity and accurately determining the dry film thickness, leading to potential insufficient or excessive film application, which can result in reduced antifouling performance and increased operational complexity.

Innovation Solution

A method using a colored antifouling paint containing a hydrolyzable resin with specific silicon-containing and metal-atom-containing groups, which provides a significant color difference between target and sub-target dry film thicknesses, allowing for visual determination of complete hiding and ensuring a uniform film thickness, thereby simplifying the application process and enhancing antifouling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional antifouling paint is used, then the coating film can be applied to the surface, but it is difficult to determine whether the prescribed film thickness has been reached by visual observation

Engineering Contradiction:
Improvefilm thickness determination accuracyVSAvoidvisual determination difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies color change principle by formulating the antifouling paint with specific pigments and opacity agents that create a distinct color transition when the film reaches the prescribed thickness. The coating appears translucent below the target thickness and becomes opaque at the target thickness, enabling visual determination without additional measurement tools.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent uses inexpensive visual indicators (color and opacity properties of the paint itself) rather than expensive permanent measurement instruments. The paint formulation includes colorants and opacity agents that serve as built-in thickness indicators, eliminating the need for specialized thickness measurement equipment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Area of stationary object

If painting is carried out on large underwater structures using crane truck, then the entire surface can be coated, but uniform film thickness application is difficult to achieve

Engineering Contradiction:
Improvecoating area coverageVSAvoidfilm thickness uniformity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent implements self-service principle by enabling the coating system to self-indicate its application status. The visual feedback mechanism (color transition from translucent to opaque) allows operators to self-correct application techniques in real-time, ensuring uniform thickness across large surfaces without requiring external measurement or supervision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback mechanism through the visual appearance of the coating film. The transition from translucent to opaque state provides immediate visual feedback to the operator about whether the prescribed thickness has been achieved, allowing real-time adjustment of application rate and technique to maintain uniformity across large areas.

Inventive Principle:
Principle #23Feedback

3Quantity of substance

If insufficient film thickness is applied, then painting cost is reduced, but antifouling performance deteriorates and effective antifouling period is shortened

Engineering Contradiction:
Improvepaint consumptionVSAvoidantifouling performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent replaces mechanical thickness measurement systems with optical properties of the paint formulation. By utilizing the inherent optical characteristics (translucency to opacity transition) of the painted film, the system eliminates the need for physical thickness gauges or complex measurement equipment, providing simple visual confirmation of adequate thickness.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses the paint's own optical properties as a disposable, built-in thickness indicator. The color and opacity characteristics of the paint formulation serve as a single-use visual cue that disappears once the coating is complete, eliminating the need for expensive, reusable measurement instruments.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If excessive film thickness is applied, then antifouling performance is improved, but paint waste increases and operational complexity increases

Engineering Contradiction:
Improveantifouling performanceVSAvoidpaint waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent uses feedback control through visual observation. The operator continuously monitors the coating appearance during application and stops when the prescribed thickness is visually confirmed (transition to opaque state), preventing over-application and associated paint waste while maintaining adequate antifouling performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies the principle of partial action by using only the minimum necessary paint thickness required for effective antifouling performance. The visual indicator system enables precise control to achieve exactly the prescribed thickness without unnecessary excess application, optimizing paint utilization.

Inventive Principle:
Principle #16Partial or excessive action

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 method enables accurate and uniform formation of antifouling coating films with a prescribed dry film thickness, preventing organism adhesion, reducing paint waste, and improving long-term antifouling properties and resistance to cracking, while simplifying the painting process and reducing operator burden.

Implementation Method 1

containing a hydrolyzable resin and a color pigment and satisfying such conditions that (a) a coating film formed from the colored antifouling paint having a target dry film thickness T completely hides the surface of the object to be coated, (b) a color difference ΔE1 between the coating film formed from the colored antifouling paint having the target dry film thickness T and a coating film formed from the colored antifouling paint having a dry film thickness of 0.8 T is equal to or greater than 2.0

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP3135389B1Method of forming antifouling coating film
Publication Date: 2022.03.16 NIPPON PAINT MARINE COATINGS CO LTD
  • EP3135389B1 patent drawingFigure 1
  • EP3135389B1 patent drawingFigure 2
  • EP3135389B1 patent drawing

AI summary

Provided is a method of forming an antifouling coating film including the steps of [1] preparing a colored antifouling paint containing a prescribed Si-containing hydrolyzable resin and a color pigment such that a coating film having a target dry film thickness T completely hides a surface of an object to be coated, the colored antifouling paint has a color difference ΔE1 between the coating film having the thickness T and a coating film having a dry film thickness of 0.8 T, at least 2.0, and preferably the colored antifouling paint has a color difference ΔE2 between the coating film having the thickness T and a coating film having a dry film thickness of 1.2 T, less than 1, and [2] coating a surface of the object with the colored antifouling paint until the surface of the object is completely hidden by the coating film formed from the colored antifouling paint.