Bituminous Membrane Reflective Coating for Cool Roof Certification
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Solution Overview
Problem
Existing bituminous sealing membranes for low-slope roofs lack sufficient reflective properties to effectively mitigate urban heat islands, failing to meet stringent cool roof certifications like EnergyStar and California Title 24.
Innovation Solution
A white-colored bituminous sealing membrane featuring a single fibrous structure reinforced with continuous glass or polyester fibers, combined with a white coating containing TiO2 particles and white mineral fillers, which enhances solar reflectance and thermal emissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a traditional bituminous membrane structure is used, then the membrane provides basic waterproofing, but it lacks sufficient reflective properties to meet cool roof certifications
Solution Approach 1:
The patent applies a white-colored surface finish to the bituminous membrane, which fundamentally changes the optical properties of the surface. This white coating increases solar reflectance by reducing solar absorbance, enabling the membrane to meet cool roof certification requirements while maintaining its waterproofing function.
Solution Approach 2:
The patent creates a composite structure combining the bituminous membrane with a white-colored surface finish comprising multiple layers. This composite approach integrates the waterproofing properties of bitumen with the reflective properties of the white coating, achieving both functional requirements.
2Illumination intensity
If a white coating is applied to increase solar reflectance, then cool roof properties are improved, but the structural complexity increases
Solution Approach 1:
The white-colored surface finish is divided into multiple functional layers: a primer layer for adhesion, a reflective coating layer containing white pigments and TiO2 particles, and a protective top layer. This segmentation allows each layer to perform its specific function while maintaining overall structural integrity.
Solution Approach 2:
The patent optimizes parameters such as the thickness of the white coating layer, the concentration of TiO2 particles (0.1-5% by weight), and the composition of the primer to achieve the desired solar reflectance while controlling structural complexity and manufacturing feasibility.
3Stability of the object's composition
If continuous reinforcement fibers are added to the fibrous structure, then dimensional stability and crack resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the reinforcement function with the existing fibrous structure by incorporating continuous reinforcement fibers directly into the non-woven cloth during manufacturing. This integration provides dimensional stability and crack resistance while avoiding the need for separate reinforcement layers or complex assembly processes.
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 membrane achieves improved solar reflectance and thermal emissivity, meeting the requirements of EnergyStar and California Title 24 certifications, thereby reducing urban heat island effects and lowering building air-conditioning costs.
Implementation Method 1
Reflectivity or solar reflectance (SR) expresses the capacity of a surface to reflect solar radiation. This is the ratio of solar energy reflected by the surface of a material to the incident energy.
Implementation Method 2
Thermal emissivity (TE) characterizes the ability of a surface to re-emit absorbed energy in the form of infrared thermal radiation.
Implementation Method 3
The energy absorbed during the day is transmitted by conduction throughout the volume of the material and emitted as thermal radiation (IR) during the night.
Data Source
AI summary
A bituminous sealing membrane includes a bituminous layer and a surface finish in contact with the bituminous layer, the surface finish including a fibrous structure including a non-woven cloth made of glass fibers and/or polyester fibers, the lower face of which is in contact with the bituminous layer and, on the upper surface of the non-woven cloth that is not in contact with the bituminous layer, a white coating including from 0.3 to 6% by weight of TiO2 particles, from 70 to 90% by weight of one or more white mineral loads and from 8 to 25% by weight of an organic polymer free of carbon-carbon double bonds, the percentages being expressed as dry weight relative to the total dry weight of the white coating. The fibrous structure of the surface finish further includes reinforcement fibers and the bituminous sealing membrane is free of other fibrous structures.