Foamed Opacifying Layer for Single-Coat Light Blocking
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Solution Overview
Problem
Existing light-blocking materials, such as blackout curtains, require multiple coating operations and can be prone to fugitive carbon black, which spreads during handling, leading to increased shading and manufacturing inefficiencies, while maintaining light coloration and opacity is challenging, especially during high-temperature drying processes.
Innovation Solution
A foamed, opacifying element comprising a porous substrate with a dry foamed composition containing porous particles, a binder material, surfactants, and a low amount of opacifying colorant, which provides a single, light-colored, and flexible layer with improved light scattering and opacity, maintaining porosity and light-blocking properties even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple coating operations are used to achieve light-blocking properties, then opacity and light-blocking performance are improved, but manufacturing complexity and time consumption increase
Solution Approach 1:
The patent combines multiple functional layers (light-scattering layer and light-absorbing layer) into a single integrated foamed composition. This single composition contains both white light-scattering pigments and black light-absorbing pigments, allowing one coating operation to achieve the light-blocking performance that previously required multiple separate coating steps.
Solution Approach 2:
The foamed composition serves multiple functions simultaneously: it provides light scattering through white pigments, light absorption through black pigments, foam structure formation for porosity, and binder functionality. This multi-functional material replaces what previously required separate specialized materials and coating operations.
2Reliability
If carbon black is used as light-absorbing pigment, then light-blocking performance is improved, but fugitive carbon spreads during handling causing increased shading
Solution Approach 1:
The carbon black particles are encapsulated within the foam structure, nested inside the three-dimensional polymeric matrix. This physical containment prevents the carbon black from migrating or spreading during handling, while still maintaining its light-absorbing properties when the foam is in its final form.
Solution Approach 2:
The carbon black is distributed locally within specific regions of the foam structure rather than as a free surface material. This localized incorporation into the foam matrix prevents the harmful spreading effect while preserving the light-blocking function where needed.
3Reliability
If thick foam coatings are used to block sunlight, then light-blocking performance is improved, but weight of the material increases
Solution Approach 1:
The patent utilizes a foamed structure with incorporated air pockets and void spaces within the coating matrix. This porous architecture reduces the density and weight of the coating material while maintaining adequate thickness for light-blocking performance, as the foam structure provides both mechanical body and light-interacting surface area.
Solution Approach 2:
The foamed composition is a composite material combining polymeric binder, white light-scattering pigments, black light-absorbing pigments, and dispersed air cells. This composite structure achieves superior light-blocking performance per unit weight by utilizing the synergistic effects of different components rather than requiring increased mass of a single material.
4Illumination intensity
If light-colored pigments are used to maintain aesthetic appearance, then luminous reflectance is improved, but light-blocking performance deteriorates
Solution Approach 1:
The patent employs a composite pigment system containing both white light-scattering pigments (for high luminous reflectance and light color) and black light-absorbing pigments (for light-blocking performance). The combination creates a material that appears light-colored due to the dominant scattering effect while simultaneously blocking transmitted light through the absorbing pigment component.
Solution Approach 2:
Different pigment components perform different optical functions locally within the same material matrix. The white pigments dominate the surface appearance and light scattering, while the black pigments are distributed throughout to absorb transmitted light, creating localized optical effects that combine to achieve both light color and blackout 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 solution enables lightweight, flexible, and durable light-blocking materials with enhanced luminous reflectance and opacity, minimizing the escape of opacifying agents during handling and reducing manufacturing complexity and costs, while maintaining desired coloration and heat management properties.
Implementation Method 1
the porous particles having a mode particle size of at least 2 μm and up to and including 50 μm and a porosity of at least 20 volume % and up to and including 70 volume %
Implementation Method 2
at least 0.002 weight % of an opacifying colorant different from all of the one or more (c) additives, which opacifying colorant absorbs predetermined electromagnetic radiation
Implementation Method 3
the dry foamed composition comprises: (a) at least 0.1 weight % and up to and including 40 weight % of porous particles
Data Source
AI summary
Foamable aqueous compositions can be foamed and applied to porous substrates to make light-blocking dry opacifying elements. Such 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. The dry opacifying element light blocking value is at least 4 and has a luminous reflectance >40% as measured by the color space Y tristimulus value. The foamed aqueous composition has a foam density of 0.1-0.5 g/cm3.