Coating Formulations for Cementitious Substrates
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Solution Overview
Problem
Conventional surface coating systems for fiber cement substrates face challenges in achieving high hide and holdout while maintaining strong adhesion, as conventional primers often fail to adequately mask discolorations and stains, and high pigment loading can lead to poor adhesion.
Innovation Solution
The development of coating formulations that include functional pigments with specific particle sizes and oil absorption values, combined with fillers and acrylic polymers, to achieve a balanced pigment volume concentration, ensuring high opacity and adhesion without excessive pigment loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pigment loading in the primer is increased to improve hide and holdout, then the ability to mask discolorations and stains is improved, but adhesion to the substrate deteriorates
Solution Approach 1:
The patent changes the particle size parameter of the pigment from conventional larger sizes to specifically smaller sizes (0.5-2.0 micrometers average diameter). This parameter change allows the pigment to provide adequate hide and holdout while maintaining adhesion, as the smaller particles can better integrate with the polymer matrix and substrate surface without compromising bond strength.
Solution Approach 2:
The patent creates a composite pigment-polymer system where the pigment particles are dispersed in a polymer vehicle at specific concentrations. This composite approach allows the pigment to provide masking functions while the polymer matrix maintains adhesion properties, resolving the contradiction between hide/holdout and adhesion.
2Ease of operation
If conventional primers are used on fiber cement substrates, then application is simple, but the ability to adequately mask discolorations and stains is insufficient
Solution Approach 1:
The patent modifies the pigment particle size parameter to 0.5-2.0 micrometers, which provides superior light scattering and masking properties compared to conventional pigments. This enables the primer to adequately mask discolorations and stains on fiber cement substrates while maintaining ease of application through standard coating methods.
3Productivity
If top coat is applied over poorly primed cementitious substrates, then the coating process is completed, but the uniformity of color and gloss is compromised
Solution Approach 1:
The patent applies a primer formulation with specifically sized pigment particles (0.5-2.0 micrometers) as a preliminary action before applying the top coat. This preliminary priming layer creates a uniform, opaque barrier that masks substrate irregularities, ensuring that the subsequent top coat application produces uniform color and gloss without requiring multiple layers.
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 formulations provide superior hide, holdout, and mechanical characteristics, allowing for a uniform coating with fewer top coats and reduced costs, while maintaining strong adhesion to cementitious substrates.
Implementation Method 1
at least one filler, wherein the at least one filler comprises an extender that separates and spreads out the particles of the functional pigment
Implementation Method 2
functional pigments and fillers are selected for certain particle size and oil absorption... Such formulations maintain high opacity upon application to a substrate
Implementation Method 3
at least one polymer, wherein the at least one polymer comprises an acrylic polymer... providing a coating with good topcoat wet adhesion
Data Source
AI summary
Coating formulations for improving hide and holdout without sacrificing adhesion on cementitious substrates are provided. The coating formulations can achieve high hide and holdout with a low pigment volume concentration by utilizing particles with pre-selected oil absorption and particle size range. The coating formulations can be used as a functional for fiber cement substrates. When applied in combination with a top coat, the functional provides provide high hide and hold and enhanced adhesion while reducing pigment loading.