Highly reflective and emissive asphalt-based roofing membrane

Abstract

A prefabricated asphalt-based waterproof roofing membrane for use in a multi-ply asphalt-based commercial roofing system, e.g. a cap sheet that forms the exposed layer of a multi-ply built-up roofing system, is manufactured at a factory to have a highly reflective and emissive non-asphalt based elastomeric top coating layer. Preferably, a polymer primer layer is interposed between the highly reflective and emissive coating layer and an asphalt saturated and coated reinforcing substrate to keep oils and other colored components in the asphalt from exuding into the highly reflective and emissive coating layer.

Description

[0001] This patent application is a continuation-in-part of patent application Ser. No. 10 / 659,001 filed Sep. 10, 2003.BACKGROUND OF THE INVENTION [0002] The subject invention relates to asphalt-based waterproof roofing membranes used in multi-ply asphalt-based commercial roofing systems and, in particular, to a prefabricated asphalt-based waterproof roofing membrane for use in a multi-ply asphalt-based commercial roofing system, e.g. a cap sheet that forms the exposed layer of a multi-ply built-up roofing system, that is manufactured at a factory to have a highly reflective and emissive upper surface that meets EPA Energy Star and similar energy saving requirements. [0003] Asphalt-based waterproof roofing membranes, such as cap sheets, are currently manufactured in a process that includes several major process steps. The process steps for producing these black asphalt-based waterproof roofing membranes include: saturating a reinforcing substrate with asphalt (bitumen), typically an...

AI Technical Summary

Benefits of technology

The patent text describes a method for manufacturing an asphalt-based waterproof roofing membrane with a highly reflective and emissive top surface that meets current energy standards. The membrane is made by applying a reflective and emissive coating to a black asphalt saturated and coated reinforcing substrate during the manufacturing process. The coating can be applied using various techniques such as dip coating, spread coating, roll coating, spray coating, and powder coating. The membrane can also be embossed or textured for better appearance and slip-resistant surfaces. The highly reflective and emissive coating is opaque to protect the underlying asphalt layer and may contain additives to improve performance. A polymer material binder, colored with a white pigment, is used to carry and bind the reflective and emissive pigments to the asphalt layer. A polymer primer is applied between the coating and the top asphalt layer to prevent staining and discoloration of the coating. The highly reflective and emissive coating can be applied at a job site to meet the Energy Star requirements.

Problems solved by technology

Due to their irregular granular top surfaces and the intergranule spaces that reveal the black light-absorbing asphalt surfaces to which the granules are adhered, asphalt-based waterproof roofing membranes, such as cap sheets, currently on the market do not meet current EPA Energy Star reflective requirements as measured by ASTM standard E 903-Standard Test Method for Solar Absorptance, Reflectance, and Transmission of Materials Using Integrating Spheres.

This procedure leads to several problems: a waiting period of up to 30 days before the coating can be applied to the top surface of the membrane; the cost of and time required to clean the top surface of the membrane before applying the coating to the top surface of the membrane; the cost of and time involved in the labor intensive application of the coating to the top surface of the membrane; the quality and / or consistency of the application of the coating to the top surface of the membrane which is dependent on the skill and conscientiousness of the laborer; the limited service life of such coatings on the top surface of the membrane; and the requirement for the periodic maintenance and reapplication of the coating to the top surface of the membrane.

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