Waterborne Coating Microgel Stability and Gloss
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Solution Overview
Problem
Existing waterborne coating compositions face challenges in maintaining storage stability, providing resistance to oils, acids, alcohols, and abrasion, while achieving a high gloss appearance without 'spotting', especially when applied using spray equipment.
Innovation Solution
The development of waterborne coating compositions comprising a continuous phase and a dispersed phase, where the dispersed phase is a microgel formed from reactants including multiethylenically unsaturated compounds and cycloaliphatic (meth)acrylates, providing a high glass transition temperature and uniform particle size, which acts as the primary source of resin solids, ensuring chemical and stain resistance and a high gloss finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If waterborne coating compositions are formulated to provide resistance to oils, acids, and abrasion, then chemical resistance is improved, but storage stability deteriorates due to viscosity increase over time
Solution Approach 1:
The coating composition is divided into two distinct phases: a continuous phase containing water and functional additives, and a dispersed phase containing microgel particles. This segmentation allows each phase to perform its specific function - the continuous phase provides application properties and chemical resistance, while the dispersed microgel phase maintains storage stability by preventing excessive viscosity increase over time.
Solution Approach 2:
The invention uses a composite system combining organic functional components (providing chemical resistance) with an aqueous continuous phase (providing storage stability). The microgel particles act as a bridge between these two phases, containing the functional monomers and oligomers in a controlled manner that prevents premature reaction while maintaining stability during storage.
2Illumination intensity
If the coating is designed to achieve high gloss appearance, then aesthetic quality is improved, but uniformity of appearance deteriorates due to spotting when applied by spray equipment
Solution Approach 1:
The invention carefully controls the particle size parameter of the microgel, specifying a range of 50-900 nanometers with a preference for 100-500 nanometers. This parameter optimization ensures the particles are small enough to be uniformly atomized by spray equipment without clogging, while still providing sufficient light scattering for gloss appearance. The controlled particle size distribution prevents the formation of spots or uneven coverage.
3Ease of operation
If microgel particle size is reduced to improve spray application, then ease of operation is improved, but coating performance deteriorates due to insufficient resin solids
Solution Approach 1:
The invention compensates for the reduced resin solids content (achieved by using smaller microgel particles for better sprayability) by incorporating functional oligomers into the microgel structure. These oligomers provide the necessary coating performance and chemical resistance that would otherwise be lost, effectively counterbalancing the trade-off between particle size and 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
The coating compositions exhibit excellent storage stability, resistance to oleic acid, alcohols, and abrasion, along with a high gloss appearance, even when applied using various spray conditions, and are suitable for use on consumer electronics and other substrates.
Implementation Method 1
The microgel is formed from reactants comprising or, in some cases, consisting essentially of: (i) no more than 5 percent by weight, based on the total weight of the reactants, of a multiethylenically unsaturated compound, and (ii) a plurality of monoethylenically unsaturated compounds selected so as to provide a copolymer having a calculated Tg greater than 100°C and comprising a cycloaliphatic (meth)acrylate
Data Source
AI summary
Disclosed are coating compositions that include a continuous phase that includes water and a dispersed phase that includes a microgel having a mean particle size of greater than 50 nanometers. The microgel is formed from reactants selected so as to provide a copolymer having a certain calculated Tg and includes a cycloaliphatic (meth)acrylate.