Roofing membranes, compositions, and methods of making the same
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Solution Overview
Problem
Current roofing membranes face challenges in achieving a balance of properties such as adhesion, UV resistance, flame retardance, flexibility, chemical resistance, and longevity, with existing polymer systems like TPO, EPDM, and PVC exhibiting drawbacks like susceptibility to heat, color limitations, and manufacturing variability.
Innovation Solution
A roofing membrane composition featuring a top and bottom layer of silane-crosslinked polyolefin elastomers with a density less than 1.45 g/cm3, combined with a scrim layer, utilizing a silane-grafting process and specific polyolefins, silane crosslinkers, and condensation catalysts to enhance material properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If TPO membranes are used, then they are widely available and affordable, but they are susceptible to deterioration when exposed to high heat and solar UV radiation
Solution Approach 1:
The patent uses composite materials by combining polyolefin elastomer with silane crosslinking agents and flame retardant additives to create a multi-functional roofing membrane that simultaneously achieves affordability, heat resistance, and UV resistance through material composition rather than single-material reliance
2Ease of manufacture
If EPDM membranes are used, then they are made from readily available synthetic rubber, but roughly 95% are black while regulators push for white roofing membranes
Solution Approach 1:
The patent changes the color parameter of the roofing membrane by using polyolefin elastomer as a base material that can be produced in white or light colors, and incorporating titanium dioxide and other pigments to achieve various color options while maintaining the readily available synthetic rubber foundation
3Strength
If PVC membranes are used, then they offer excellent puncture, heat-weldability, and heat resistant qualities, but they can be expensive to manufacture and suffer from variability in properties
Solution Approach 1:
The patent applies homogeneity by using silane crosslinking technology to create uniform crosslinked structures throughout the polyolefin elastomer matrix, ensuring consistent physical and chemical properties across different batches and manufacturers, thereby reducing property variability while maintaining excellent strength characteristics
4Productivity
If traditional polymer compositions are used, then they provide basic roofing functionality, but they exhibit production variability and lack superior durability over longer periods
Solution Approach 1:
The patent applies preliminary action by pre-crosslinking the polyolefin elastomer with silane agents before the membrane is installed on the roof. This pre-crosslinking creates a stable, durable network structure that resists degradation over time and ensures consistent performance, eliminating the need for post-installation curing and reducing production variability
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 a roofing membrane with improved durability, reduced production variability, and enhanced material properties like tensile strength, elongation, and flame retardance, while being simpler, lighter, and more color-neutral.
Implementation Method 1
a silane crosslinker, a grafting initiator, and a condensation catalyst
Implementation Method 2
a silane crosslinker, a grafting initiator, and a condensation catalyst
Data Source
AI summary
A roofing membrane and a method of making the same is provided. The roofing membrane includes a top layer having a flame retardant and a first silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm3; a scrim layer; and a bottom layer having a flame retardant and a second silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm3. The top and bottom layers of the roofing membrane both exhibit a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70° C.).