Foamed Opacifying Coating for Lightweight Light-Blocking Articles
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Solution Overview
Problem
Existing light-blocking materials, such as blackout curtains, require multiple coating operations and can have issues with fugitive carbon black pigments becoming dislodged during use, leading to uneven shading and increased manufacturing costs, while also lacking in flexibility and porosity to effectively scatter light and maintain opacity at high temperatures.
Innovation Solution
A method using a foamable aqueous composition with porous particles, a binder material, surfactants, and a low amount of opacifying colorants like carbon black, which is aerated and applied to a porous substrate, then dried and densified to create a single, light-colored, opacifying layer that maintains porosity and light-scattering properties even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple coating operations are used to create light-blocking materials, then light-blocking effectiveness is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent combines multiple functional layers (light-blocking carbon black layer and light-scattering white pigment layer) into a single composite coating layer. This is achieved by incorporating both carbon black and titanium dioxide pigments within the same foam structure, allowing one coating operation to deliver the light-blocking effectiveness that previously required multiple separate layers, thereby simplifying manufacturing while maintaining performance.
Solution Approach 2:
The invention creates a composite foam material containing both carbon black particles (for light absorption) and titanium dioxide particles (for light scattering) distributed within the same polymer matrix. This composite structure enables simultaneous light-blocking and light-scattering functions in a single layer, eliminating the need for multiple coating operations and reducing manufacturing complexity.
2Reliability
If carbon black pigment is used in light-absorbing layers, then light-blocking effectiveness is improved, but the pigment becomes fugitive and soils other layers
Solution Approach 1:
The patent encapsulates carbon black particles within the foam structure, nesting them inside the polymer matrix along with titanium dioxide particles. This nested configuration prevents the carbon black from becoming fugitive and soiling adjacent layers, as it is physically contained within the foam cells rather than being exposed on the surface or in separate layers that can contact each other during handling.
Solution Approach 2:
By creating a composite foam containing both carbon black and titanium dioxide particles embedded in the polymer matrix, the invention stabilizes the carbon black pigment in place. The composite structure prevents pigment migration and soiling while maintaining the light-blocking effectiveness of the carbon black, solving the fugitive pigment problem.
3Reliability
If thick foam coatings are used to block light, then light-blocking effectiveness is improved, but material weight increases
Solution Approach 1:
The patent utilizes a foamed polymer structure with numerous air-filled cells throughout the material. This porous architecture provides effective light-blocking through multiple light scattering events at the foam cell interfaces and pigment particles, while the air-filled voids significantly reduce the material density and weight compared to solid thick coatings, achieving light-blocking effectiveness with reduced weight.
Solution Approach 2:
The composite foam combining carbon black and titanium dioxide particles in a porous polymer matrix achieves efficient light-blocking with reduced thickness and weight. The synergistic interaction between the light-absorbing carbon black, light-scattering titanium dioxide, and foam structure provides superior light-blocking performance per unit weight compared to traditional solid coatings.
4Illumination intensity
If light scattering pigments are used to create light-colored blackout curtains, then aesthetic appearance is improved, but opacity decreases requiring thicker coatings
Solution Approach 1:
The invention creates a composite foam containing both light-scattering titanium dioxide particles (providing light coloration) and light-absorbing carbon black particles (providing opacity). The synergistic interaction between these two pigments within the foam structure enables the material to maintain a light-colored appearance while achieving effective light-blocking opacity, resolving the trade-off between aesthetics and functionality.
Solution Approach 2:
The patent distributes different pigment types throughout the foam structure, with carbon black particles providing localized light absorption and titanium dioxide particles providing localized light scattering. This spatial distribution of different functional qualities within the same material enables simultaneous light coloration and opacity without requiring increased thickness.
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 solution provides lightweight, flexible, and highly effective light-blocking materials with improved luminosity and reduced fugitive colorant issues, allowing for simpler manufacturing and enhanced heat management in environments like hospitals and extreme climates.
Implementation Method 1
aerating the foamable aqueous composition to provide a foamed aqueous composition
Implementation Method 2
maintain porosity and light-scattering properties
Implementation Method 3
opacifying colorant absorbs predetermined electromagnetic radiation
Implementation Method 4
drying the foamed aqueous composition to provide a dry foamed composition
Data Source
AI summary
A method for providing a foamed, opacifying element includes providing a foamable aqueous composition, aerating it to a foam density of 0.1-0.5 g/cm3, applying the foamed aqueous composition to a porous substrate, drying, and densifying the dried layer. Such foamable aqueous compositions have 0.05-15 weight % of porous particles; at least 20 weight % of a binder; at least 0.0001 weight % of additives (including a surfactant); water; and at least 0.001 weight % of an opacifying colorant. Each porous particle includes a continuous polymeric phase and discrete pores; a mode particle size of 2-50 μm; and a porosity of 20-70 volume %. The continuous polymeric phase Tg is >80° C. and has a polymer viscosity of 80-500 centipoises at an ethyl acetate shear rate of 100 sec−1 at a concentration of 20 weight % at 25° C.