Phosphorus Acid Functionalized Core-Shell Polymers for TiO2 Hiding Efficiency
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Solution Overview
Problem
Current opaque polymer additives in pigmented coating formulations, such as paints, do not effectively enhance hiding efficiency without increasing the costly TiO2 load or maintaining its levels, limiting their ability to improve opacity.
Innovation Solution
Phosphorus acid functionalized core-shell polymer particles are formed by staged addition of phosphorus acid monomers during emulsion polymerization, creating composites with TiO2 particles that enhance hiding efficiency in paint formulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional opaque polymer additives are used in pigmented coating formulations, then the polymer provides some hiding enhancement, but the hiding efficiency is insufficient without increasing the costly TiO2 load
Solution Approach 1:
The patent applies composite materials by combining organic polymer particles with inorganic TiO2 particles to form a hybrid opaque additive. The composite structure integrates the high refractive index benefit of TiO2 with the polymer matrix, creating a synergistic effect that enhances hiding efficiency more effectively than conventional polymer additives alone, while allowing reduction of overall TiO2 load in the formulation.
Solution Approach 2:
The patent applies local quality by creating polymer particles with non-uniform internal structure featuring voids or cavities distributed throughout the particle volume. These localized void regions create additional light scattering centers within the polymer matrix, enhancing the hiding efficiency at specific locations within the coating film without requiring increased TiO2 concentration throughout the entire formulation.
2Illumination intensity
If TiO2 load is increased to improve hiding efficiency, then hiding performance improves, but formulation cost increases due to TiO2 being comparatively expensive
Solution Approach 1:
The patent applies copying by creating artificial light scattering structures (voids/cavities) within the polymer particles that replicate the light scattering function of TiO2. These internal voids serve as substitutes for additional TiO2, providing comparable hiding enhancement through structural design rather than material substitution, thereby avoiding the cost increase associated with higher TiO2 loading.
3Illumination intensity
If conventional opaque polymers are used to maintain TiO2 levels, then hiding is maintained, but hiding efficiency cannot be improved
Solution Approach 1:
The patent applies segmentation by dividing the polymer particle into distinct phases or regions, including void spaces separated by polymer walls. This segmented internal architecture creates multiple interfaces for light scattering, enhancing hiding efficiency. The segmented structure provides adaptability by allowing optimization of void size, distribution, and polymer wall thickness to achieve improved hiding performance while maintaining compatibility with existing TiO2 levels in the formulation.
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 phosphorus acid functionalized core-shell polymer particles significantly improve hiding efficiency in paint formulations by forming effective composites with TiO2 particles, offering enhanced opacity without increasing TiO2 load, as demonstrated by increased particle size and void fraction measurements.
Implementation Method 1
copolymerized with said nonionic ethylenically unsaturated monomers under emulsion polymerization conditions
Implementation Method 2
consisting essentially of: a polymer or copolymer of one or more monomers selected from the group consisting of styrene, methyl methacrylate, acrylonitrile, and t-butyl acrylate; and from 0.1 to 5 weight percent structural units of a phosphorus acid monomer
Implementation Method 3
The phosphorus acid functionalized core-shell polymer particles are useful in forming composite with TiO2 particles, which composites improve hiding efficiency in paint formulations
Data Source
AI summary
The present invention relates to opaque polymers functionalized with phosphorous acid groups, composites of TiO2 particles and the opaque polymers, and methods for their preparation. The composites are useful in coatings formulations and have been shown to exhibit improved hiding benefits in coated substrates over compositions containing non-functionalized opaque polymer and TiO2.