Multilayer Coating Film Simultaneous Curing Brightness
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Solution Overview
Problem
Existing methods for forming multilayer coating films, particularly with water-based paints, face challenges such as decreased brightness due to pigment orientation disorder, and issues with dripping resistance and image clarity.
Innovation Solution
A method involving the simultaneous curing of a multilayer coating film comprising three or four layers, using a first water-based paint with specific components like hydroxyl group-containing acrylic resin, crosslinking agents, and acrylic-urethane composite particles, to achieve improved film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wet-on-wet coating with water-based paint is used to form multilayer coating film, then environmental burden is reduced and energy consumption is lowered, but the orientation of effect pigment becomes disordered resulting in decreased brightness
Solution Approach 1:
The patent applies preliminary action by preheating the uncured first base coating film to 40-100°C for 1-15 minutes before applying the second base effect paint. This preliminary heating step prepares the coating surface to maintain pigment orientation during the subsequent wet-on-wet coating process, preventing the brightness decrease that would otherwise occur with water-based paints
Solution Approach 2:
The patent applies parameter changes by controlling the paint solid content concentration of the second base effect paint within a specific range (5-50 mass%) and adjusting the preheating temperature and time parameters. These parameter optimizations ensure proper pigment orientation while maintaining the energy efficiency and environmental benefits of water-based coating systems
2Adaptability or versatility
If two types of water-based base paints are applied sequentially in wet-on-wet manner, then coating flexibility and adaptability are improved, but dripping resistance and image clarity deteriorate
Solution Approach 1:
The patent applies preliminary action by preheating the uncured first base coating film before applying the second paint layer. This preliminary heating step improves the flow characteristics and leveling of the second paint application, preventing dripping and maintaining image clarity while preserving the flexibility of using multiple water-based paint types
Solution Approach 2:
The patent optimizes the paint solid content concentration parameter of the second base effect paint to 5-50 mass%, which improves the coating's flowing properties and prevents dripping during wet-on-wet application, thereby maintaining image clarity while preserving coating flexibility
3Illumination intensity
If effect pigment is applied at high concentration to achieve metallic appearance, then brightness and metallic luster are improved, but pigment orientation becomes more difficult to maintain resulting in decreased brightness
Solution Approach 1:
The patent applies preliminary action by preheating the coating surface before applying the high-concentration effect pigment paint. This preliminary heating step creates optimal conditions for pigment orientation by adjusting the viscosity and flow characteristics of the paint, enabling high pigment concentration while maintaining metallic luster and brightness
Solution Approach 2:
The patent optimizes the paint solid content concentration parameter to 5-50 mass% for the second base effect paint, which is the optimal range for maintaining pigment orientation while achieving desired metallic appearance. This parameter optimization allows high pigment concentration without sacrificing brightness
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 the formation of multilayer coating films with excellent dripping resistance, image clarity, and brightness, even when using water-based paints, by maintaining the orientation of effect pigments and ensuring proper film formation.
Implementation Method 1
a hydroxyl group-containing acrylic resin (A), a crosslinking agent (B)
Implementation Method 2
acrylic-urethane composite particles (C) containing an acrylic resin component having an acid value less than or equal to 20 mg KOH/g
Implementation Method 3
the volatilization rate of water, which is the diluting solvent, is slow
Data Source
AI summary
The purpose of the present invention is to provide a method for forming a multilayer coating film whereby it is possible to form a multilayer coating film that exhibits superior sag resistance, mirror finish, and luster. A first coating film of a first aqueous coating material (P1) having a specific composition, a second colored coating film of a second aqueous colored coating material (P2) that has a specific coating material solid component concentration (NVP2) and contains a lustrous pigment (BP2), and a clear-coat coating film of a clear coat coating material (P3) are formed on an object to be coated, and a multilayer coating film including the first coating film, the second colored coating film, and the clear-coat coating film is heated to cure the coating films simultaneously.