Opacifying Polymer Dispersion for One-Coat Hide Paints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing architectural coatings struggle to achieve one-coat hiding with high hiding and whiteness due to the crowding effect of high TiO2 levels, which reduces scattering efficiency and Y-reflectance.
Innovation Solution
Aqueous dispersion of multistage polymer particles with a water-occluded core, a polymeric shell, and a superposing binder layer, combined with a specific colorant and opacifying inorganic pigment, within a narrow concentration range, to enhance light scattering and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high levels of TiO2 are used to achieve high hiding, then hiding is improved, but scattering efficiency is reduced due to the crowding effect
Solution Approach 1:
The patent applies local quality by creating multistage polymer particles with distinct functional zones: a water-occluded core for light scattering and a polymeric shell with binder layer for adhesion and protection. This spatial differentiation allows each region to optimize its local function without interfering with the other, resolving the crowding effect while maintaining high hiding.
Solution Approach 2:
The invention uses composite materials by combining inorganic opacifying pigment particles with multistage polymer particles having different Tg values. The core-shell-binder structure creates a composite system where each material contributes its unique properties: the core provides scattering, the shell provides structural integrity, and the binder provides adhesion, collectively achieving high hiding without TiO2 crowding.
2Reliability
If light absorption is used to increase hiding, then hiding is improved, but whiteness is attenuated
Solution Approach 1:
The patent segments the light interaction function by assigning different particles to different roles: multistage polymer particles with water-occluded cores handle light scattering to maintain whiteness, while colorant particles handle light absorption for hiding. This functional segmentation allows both hiding and whiteness to be optimized simultaneously without one compromising the other.
Solution Approach 2:
The invention changes the physical parameters of the polymer particles by controlling the Tg of different layers (core vs. shell vs. binder) and optimizing particle size distribution. These parameter changes enhance light scattering efficiency across different wavelengths, improving both hiding and whiteness performance while reducing reliance on absorbing colorants.
3Quantity of substance
If other pigments are used to reduce TiO2 loading, then TiO2 loading is reduced, but hiding or Y-reflectance is reduced to levels outside requirements
Solution Approach 1:
The multistage polymer particles serve multiple functions simultaneously: they provide light scattering for hiding, contain water for controlled release and adhesion, offer structural integrity through the shell, and provide binding through the binder layer. This multi-functionality allows them to replace TiO2's hiding function while adding beneficial properties, reducing TiO2 loading without compromising performance.
Solution Approach 2:
The water-occluded core creates a porous or cavitated structure that enhances light scattering through multiple internal reflections and refractions. This porous architecture increases the effective scattering cross-section of each particle, allowing reduced pigment loading while maintaining high hiding and Y-reflectance performance.
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
Achieves a one-coat hide paint formulation with a contrast ratio of at least 99.5% and Y-reflectance of at least 91.0% at a wet film thickness of 50.8-101.6 µm (2-4 mil), overcoming the limitations of traditional formulations.
Implementation Method 1
a colorant that absorbs light in the range of from 500 nm to 600 nm
Implementation Method 2
Hiding and whiteness are achieved using high refractive index particles such as TiO2 particles
Data Source
AI summary
The present invention relates to a composition comprising 1) an aqueous dispersion of multistage opacifying polymer particles with a superposing binder layer; 2) a colorant; and 3) inorganic opacifying pigment particles. The composition of the present invention is useful for one coat hide paint formulations.