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POLYMERIC MIRROR FILM

IP.com Disclosure Number: IPCOM000220236D
Publication Date: 2012-Jul-26

Publishing Venue

The IP.com Prior Art Database

Related People

Keith Weller: CONTACT [+2]

Abstract

A highly reflective, highly durable polymeric mirror film having a multi-layer coating system for use in concentrated solar energy systems is disclosed.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 10% of the total text.

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MOMENTIVE PERFORMANCE MATERIALS INC.

Author: Keith Weller

Keith.Weller@momentive.com +1-518-233-3216 4information@momentive.com

POLYMERIC MIRROR FILM ABSTRACT

    A highly reflective, highly durable polymeric mirror film having a multi-layer coating system for use in concentrated solar energy systems is disclosed.

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POLYMERIC MIRROR FILM

            BACKGROUND OF THE INVENTION [0001]Concentrated solar energy systems, such as concentrated photovoltaic (CPV) and concentrated solar power (CSP) technologies, have the potential to become more commercially viable by using concentrator mirror technologies that are lower cost, lighter weight, and less prone to breakage than existing glass mirror-based systems.

[0002]Three major mirror technologies have been previously developed and evaluated in CSP technologies: glass mirrors, polymeric mirror films, and front surface mirrors. [0003]Glass mirrors are glass sheets of a thickness of 1 mm or greater that are metallized with silver or aluminum and then protected with a copper backing and/or back-protective coatings. Silvered glass has respectable reflectance (90%-95%), good weatherability, and scratch resistance. Its drawbacks include low initial reflectance due to absorption loss, heavy weight of the glass, and relatively high cost.

[0004]Solar reflector technologies for glass mirrors have been investigated in the past. Traditional thick-glass mirrors (> 1 mm) have been commercially deployed and have proven durability in field service, but are heavy and too costly ($4-6/ft2). Thin-glass mirrors (~1 mm), although having acceptable performance once installed, have proven to be too fragile and difficult to handle. This negatively impacts the labor costs associated with installation and maintenance. In addition, long-term durability remains a concern for glass mirrors of any thickness, unless they are coated with an environmentally- unfriendly copper backing and lead-based back-protective paint.

[0005]Polymeric mirror films are composed of a silvered thin film polymeric superstrate laminated on a rigid structure. Silvered polymeric films were initially developed in the 1980s and represented a promising approach to achieve a low cost solar mirror with lighter weight and good design flexibility. However, such films generally suffer from insufficient abrasion resistance and long-term weatherability.

[0006]The Advanced Solar Reflective Mirror (ASRM) project was an attempt to solve the abrasion and weatherability deficiencies of the silvered polymeric film mirrors. With ASRM, an ion-bean-assisted-deposition (IBAD) technique is used to deposit a very hard

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and UV-transparent alumina layer over a silver reflective layer. However, IBAD is a very slow process and optimization of the deposition conditions to achieve required performance at a high deposition rate is difficult. In its current state, roll-to-roll manufacturing using IBAD is still cost prohibitive and provides low...