Stain-Resistant Coating Composition with Composite Particulate Solids
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Solution Overview
Problem
Current coating technologies face challenges in achieving stain resistance while maintaining a high pigment volume concentration (PVC) without using volatile organic compounds (VOCs), as high PVC levels often result in poor compactness and increased stain susceptibility.
Innovation Solution
An aqueous stain-resistant coating composition utilizing self-crosslinkable polymeric particles with a low glass transition temperature (Tg) and a combination of sheet-like and sphere-like particulate solids, achieving a PVC of 45% or more without VOCs, which enhances film formation and compactness, and improves barrier properties against contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high pigment volume concentration (PVC) is used to improve coating compactness, then coating durability is improved, but pore formation increases leading to poor stain resistance
Solution Approach 1:
The patent uses a composite particulate structure combining hydrophobic particles (e.g., titanium dioxide, zinc oxide) with hydrophilic particles (e.g., calcium carbonate, barium sulfate) in specific ratios. This composite approach creates a coating that maintains high PVC (40-60%) while the hydrophobic particles fill pores and the hydrophilic particles provide spacing, preventing pore formation and maintaining both compactness and stain resistance against aqueous and oily contaminants
Solution Approach 2:
The patent optimizes the weight ratio of hydrophobic to hydrophilic particulate solids within 1:4 to 4:1, and controls PVC within 40-60%, with glass transition temperature of film-forming resin between -20°C to 50°C. These parameter optimizations ensure the coating maintains adequate spacing between particles preventing pore formation while achieving high compactness and dual stain resistance
2Object-affected harmful factors
If surface modifiers are added to reduce surface tension and improve stain resistance, then initial stain resistance is improved, but modifiers migrate to surface causing reduced stain resistance after scrubbing
Solution Approach 1:
The patent employs the inherent surface properties of hydrophobic particulate solids (e.g., titanium dioxide, zinc oxide) to provide stain resistance without adding separate surface modifiers. These particles naturally repel both aqueous and oily contaminants through their surface characteristics, eliminating the need for migratory modifiers and ensuring long-term durability maintains stain resistance even after multiple scrubs
Solution Approach 2:
The patent removes the need for traditional surface modification components by directly utilizing the surface properties of hydrophobic particulate solids. This extraction of the surface modification function into the particulate structure itself prevents the migration problem associated with separate modifier additives while maintaining effective stain resistance
3Object-affected harmful factors
If high Tg resin is used to reduce adhesion to contaminants, then stain resistance is improved, but additional coalescing agents are required leading to VOC emissions
Solution Approach 1:
The patent optimizes the glass transition temperature of the film-forming resin within -20°C to 50°C, allowing adequate film formation without requiring high Tg resins that would necessitate coalescing agents. This parameter optimization enables the coating to achieve proper film formation and flexibility at lower temperatures, eliminating the need for VOC-containing coalescing agents while maintaining stain resistance through the hydrophobic particulate structure
Solution Approach 2:
The patent removes the need for coalescing agents by using lower Tg film-forming resins that can self-form films at application temperatures. This extraction of the coalescing function eliminates VOC emissions while the stain resistance is provided by the hydrophobic particulate solids rather than high Tg resin properties
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 composition achieves excellent stain resistance against both aqueous and oily contaminants, maintaining durability and chemical stability with a water contact angle between 70 to 110 degrees, even at high PVC levels, and is free from VOC emissions.
Implementation Method 1
the polymeric particles have a Tg of 10° C. or less
Implementation Method 2
aqueous dispersions of self-crosslinkable polymeric particles
Implementation Method 3
the contaminants are easily absorbed into its interior through capillary adsorption action
Data Source
AI summary
The present disclosure refers to an aqueous stain resistant coating composition, comprising, one or more aqueous dispersions of self-crosslinkable polymeric particles; and one or more particulate solids, wherein the polymeric particles have a Tg of 10° C. or less; and wherein the particulate solids comprise a combination of sheet-like particulate solids and sphere-like particulate solids in a weight ratio of 1:1 or more; and wherein the coating composition has a pigment volume concentration of 45% or more; and the coating composition is substantially free of volatile organic compounds.