Multilayer Pearl Coating for Low-Temperature Automotive Curing
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Solution Overview
Problem
Existing methods for forming multilayer films in automotive painting face challenges in achieving low temperature curing while maintaining film performance and designability, particularly for integrating metal and plastic members, and there is a demand for improved white pearl colors with high flip-flop properties.
Innovation Solution
A method involving the application of aqueous two-pack first colored coating, aqueous one-pack white color coating, aqueous one-pack interference color coating, and solvent-based two-pack clear coating materials, followed by simultaneous curing at 75° C. to 100° C. to form a multilayer film with specific composition ratios and film thicknesses, using titanium oxide-coated alumina flake pigment and hydroxyl group-containing resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the baking temperature is lowered to save energy, then energy consumption is reduced, but film performance such as finished appearance and water resistance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the base coating material by incorporating specific resin components (acrylic resin emulsion, water-soluble acrylic resin, melamine resin) and plasticizers in optimized ratios. This chemical parameter modification enables the coating to achieve proper curing and film performance at lower temperatures without sacrificing quality.
Solution Approach 2:
The patent uses a composite base coating material containing multiple resin types (acrylic resin emulsion, water-soluble acrylic resin, melamine resin) combined with specific plasticizers. This composite formulation provides both low-temperature curability and high film performance, resolving the contradiction between energy saving and quality maintenance.
2Loss of energy
If a 3-coat 1-bake system is used to omit the bake curing step after intermediate coating material application, then energy consumption is reduced, but the coating process complexity increases and film quality may deteriorate
Solution Approach 1:
The patent merges the curing functions into a single final bake step that simultaneously cures the base coating and clear coating layers. By combining multiple curing operations into one step and using a base coating material designed for low-temperature curing, the process reduces energy consumption while maintaining manageable complexity.
3Temperature
If aqueous base coating material contains specific resin components and plasticizers in optimized ratios, then low temperature curing properties are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for resin components (10-60% acrylic resin emulsion, 5-40% water-soluble acrylic resin, 20-40% melamine resin) and plasticizer content (10-40 parts by mass per 100 parts resin solid content). These optimized parameters enable low-temperature curing while providing clear manufacturing guidelines to control precision requirements.
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 achieves a whitish multilayer film with excellent low temperature curing properties, finished appearance, and designability on both metal and plastic members, enhancing the visual effects of automobile outer panels.
Implementation Method 1
heating the uncured first colored coating film, the uncured white coating film, the uncured interference color coating film, and the uncured clear coating film formed in the steps (1) to (5) at a temperature of 75° C. or more and 100° C. or less to simultaneously cure these coating films
Data Source
AI summary
A method for forming a multilayer film, including: a step (1) of applying an aqueous two-pack first colored coating material on an automobile outer panel to form an uncured first colored coating film; a step (2) of applying an aqueous one-pack white color coating material on the uncured first colored coating film to form an uncured white coating film; a step (3) of setting the uncured white coating film for 4 minutes or more such that a resultant coating film has a solid content of 50% by mass or more; a step (4) of applying an aqueous one-pack interference color coating material on the uncured white coating film having the solid content of 50% by mass or more to form an uncured interference color coating film; a step (5) of applying a solvent-based two-pack clear coating material on the uncured interference color coating film to form an uncured clear coating film; and a step (6) of heating the coating films formed in the steps (1) to (5) at a temperature of 75° C. or more and to 100° C. or less to simultaneously cure the coating films.