SpecTips: Performance Benefits of KEE HP Roof Membranes
KEE HP (High Performance) Modified PVC Membrane
Liquid plasticizers are an essential ingredient when making a flexible PVC material, such as PVC roof membrane. Over time, liquid plasticizers can be extracted from the membrane thanks to environmental and job-specific factors like extreme heat and UV exposure, acid rain, harsh chemicals, and incompatible products or materials.Because liquid plasticizers contribute directly to the flexibility of the PVC membrane, plasticizer loss can reduce flexibility, decreasing the membrane's long-term performance.
Ketone Ethylene Ester, or "KEE", is a solid, flexible, high molecular weight polymer that is non-migrating. KEE serves as a replacement to some of the liquid plasticizers in PVC membrane. In addition to improving long-term flexibility, the KEE polymer provides several other benefits to the membrane. It increases chemical resistance (even beyond that of standard PVC membrane), improves aesthetics by having a greater resistance to dirt pick-up and microbial growth, and provides the sheet with a higher tolerance to extreme temperature fluctuations.
KEE HP (High Performance) polymer is an extension of the standard KEE grade. With an even higher molecular weight, a lesser amount is needed to achieve equal or greater benefits, compared with higher amounts of standard KEE. Because higher concentrations of KEE can impact the weldability of the membrane, KEE HP enables a wider window of weldability compared with standard KEE, while retaining all the performance benefits.
SPECTIP
Note: PVC KEE HP membrane is not KEE – it is KEE HP, a "High Performance" Polymer and is NOT specified under Section 075416 "Ketone Ethylene Ester (KEE) Roofing".
- Ketone Ethylene Ester (KEE) is defined as containing "not less than 50 percent by weight of the polymer content of the sheet when tested in accordance with ASTM D8154".
- PVC KEE HP follows the standard for PVC, ASTM D4434, and is a Type IV membrane.
- Use Specification Section 075419 "Polyvinyl-Chlorine (PVC) Roofing" – Part 2 – Products – Add PVC KEE HP as defined by ASTM D4434, Type IV.
For more information, check out the following resources:
Sure-Flex KEE HP Membrane Sell Sheet
Sure-Flex KEE HP Membrane Product Data Sheet
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