Coating Film Whiteness via Polymer Phase Separation
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Solution Overview
Problem
Existing methods for forming coating films struggle to precisely control surface properties and optical characteristics, particularly in achieving high whiteness and concealment without using inorganic pigments.
Innovation Solution
A method involving the application of a liquid composition containing solvents A and B with specific boiling points and Hansen solubility parameters, along with a polymer C that is soluble in solvent A but insoluble in solvent B, followed by the application of water droplets to induce phase separation and form secondary particles with a core-shell structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If inorganic pigments are used to achieve high whiteness and concealment, then optical characteristics are improved, but manufacturing complexity and environmental concerns increase
Solution Approach 1:
The invention extracts and eliminates inorganic pigments from the coating formulation, achieving whiteness and concealment through organic polymer phase separation structures instead, thereby reducing manufacturing complexity and environmental concerns
Solution Approach 2:
The invention changes the mechanism from pigment-based optical properties to polymer concentration and phase separation parameter control, using specific Hansen solubility parameters and boiling point differences to achieve the desired optical characteristics without inorganic additives
2Reliability
If inorganic pigments are used to achieve high concealment, then optical characteristics are improved, but the coating formulation complexity increases
Solution Approach 1:
The invention removes inorganic pigments from the formulation and replaces their concealment function with a carefully designed polymer-solvent system that achieves similar optical properties through phase separation rather than pigment particles
Solution Approach 2:
The invention creates a composite structure within the coating film through phase separation, forming distinct polymer-rich and polymer-poor regions that work together to provide concealment without requiring inorganic pigment additives
3Ease of operation
If conventional coating methods are used, then application is simple, but surface property control precision is insufficient
Solution Approach 1:
The invention introduces specific parameter ranges (Hansen solubility parameters, boiling points, polymer concentrations) that enable precise control of phase separation and surface properties while maintaining a relatively simple two-step application process
Solution Approach 2:
The invention utilizes phase separation transitions during drying to automatically control surface properties, where the polymer separates into distinct phases based on the defined solubility parameters, providing self-organized precision without complex application equipment
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
This method enables the formation of a coating film with high whiteness and excellent concealment properties, achieved through the controlled formation of secondary particles and their alignment in a cell-shaped convection structure, without the need for inorganic pigments.
Implementation Method 1
a method involving the application of a liquid composition containing solvents A and B with specific boiling points and Hansen solubility parameters, along with a polymer C that is soluble in solvent A but insoluble in solvent B, followed by the application of water droplets to induce phase separation and form secondary particles with a core-shell structure
Implementation Method 2
a boiling point of the solvent A is lower than 99°C
Implementation Method 3
the solvent B is compatible with the solvent A
Data Source
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AI summary
The present invention relates to a method for forming a coating film including a step 1 of applying a liquid composition I containing a solvent A, a solvent B, and a polymer C to a base material; and a step 2 of applying droplets of a liquid II containing water to the liquid composition I on the base material as applied in the step 1, wherein a boiling point of the solvent A is lower than 99°C, and a distance Ra of the Hansen solubility parameter of the solvent A to water is 36 or less; a boiling point of the solvent B is 150°C or higher, and a distance Ra of the Hansen solubility parameter of the solvent B to water is 40 or more; and the solvent B is compatible with the solvent A, the polymer C is soluble in the solvent A but insoluble in the solvent B, and an average diameter d of the droplets applied in the step 2 is 0.01 pm or more and 50 pm or less.