Stable Aqueous Composite Particles via Adsorbing Polymer Spacing
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Solution Overview
Problem
The efficacy of titanium dioxide (TiO2) as a hiding pigment in paints is reduced when TiO2 particles come too close together during film formation, leading to instability in aqueous compositions and poor coating performance.
Innovation Solution
Admixing TiO2 particles with adsorbing emulsion polymer particles at or below the critical composite ratio within an equilibrated viscosity range of 200 cps to 4000 cps and at a mixing intensity greater than 2 hp/kgal to form stable composite particles, which improves the spacing and efficiency of TiO2 usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TiO2 particles are allowed to come close together during film formation, then the coating can be formed, but the hiding performance deteriorates and stability is reduced
Solution Approach 1:
An adsorbing emulsion polymer is introduced as an intermediary substance that coats the TiO2 particles, maintaining optimal spacing between them. This intermediary layer prevents direct contact between TiO2 particles while ensuring proper distribution and spacing in the dried coating, thereby maintaining both stability and hiding performance.
Solution Approach 2:
The invention controls the composite ratio parameter (ratio of TiO2 to adsorbing emulsion polymer) and viscosity parameters to optimize particle spacing. By adjusting these parameters within specific ranges, the invention achieves proper TiO2 particle distribution that maintains stability while preventing excessive closeness that would reduce hiding performance.
2Manufacturing precision
If TiO2 particles are spaced further apart using adsorbing emulsion polymer, then hiding performance improves, but the complexity of the composition increases
Solution Approach 1:
The adsorbing emulsion polymer serves multiple functions simultaneously: it acts as a binder for TiO2 particles, provides the necessary spacing between particles, contributes to film formation, and stabilizes the aqueous composition. This multi-functionality achieves improved TiO2 spacing and hiding performance without significantly increasing composition complexity.
3Reliability
If mixing intensity is increased to improve composite particle formation, then stability improves, but energy consumption increases
Solution Approach 1:
The adsorbing emulsion polymer is pre-formulated with specific adsorbing groups and properties before mixing with TiO2. This preliminary preparation ensures that upon mixing, the polymer rapidly and efficiently adsorbs onto TiO2 particles, achieving stable composite formation without requiring excessive mixing energy. The preliminary design of the polymer structure facilitates easy and energy-efficient composite particle formation.
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 results in a stable aqueous composition with reduced grit levels and enhanced coating properties, including improved hiding performance and gloss, by effectively utilizing TiO2 as a hiding pigment.
Implementation Method 1
adsorbing emulsion polymer particles... admixing TiO2 particles and adsorbing emulsion polymer particles
Data Source
AI summary
This invention provides a method for forming a stable aqueous composition including composite particles by admixing TiO2 particles and adsorbing emulsion polymer particles at or below the critical composite ratio to an equilibrated viscosity range of from 200 cps to 4000 cps. Also provided is a method for forming a stable aqueous composition including composite particles by admixing TiO2 particles and adsorbing emulsion polymer particles at a mixing intensity of greater than 2 hp/kgal. A method for providing a coating including composite particles is also included.