Acrylic photovoltaic module backsheet

The invention relates to an acrylic layer (in the form of a coating, film or sheet) useful as part of a photovoltaic module backsheet. The acrylic layer contains at least 40 percent of one or more acrylic polymers, including an acrylic polymer matrix and optionally acrylic impact modifiers. The acrylic polymer is preferably a polymer, copolymer, or terpolymer containing at least 50 weight percent of methylmethacrylate monomer units. The acrylic layer is flexible and optionally contains high levels of white pigment. It may also contain fluoropolymers such as polyvinylidene fluoride to improve weathering, processibility and film formation. The acrylic layer adheres to a polymer support layer such as polyethylene terephthalate (PET). A preferred substrate is PET that is pre-treated to improve adhesion, but unprimed PET can also be used. The backsheet provides excellent weatherability, environmental stability and reflectivity as part of a photovoltaic module.