Photovoltaic modules with a thermoplastic hot-melt adhesive layer and a process for their production

Process for the production of the photovoltaic modules comprising:

• A) at least one outer covering layer on the front side, facing the energy source, of glass or an impact-resistant, UV-stable, weathering-stable, transparent plastic with a low permeability to water vapor,
• B) at least one outer layer on the reverse side, facing away from the energy source, of glass or a weathering-stable plastic with a low permeability to water vapor, and
• C) at least one adhesive layer of plastic between A) and B) in which at least one or more solar cells connected electrically to one another are embedded,
• wherein the adhesive layer of plastic C) comprises an aliphatic, thermoplastic polyurethane with a hardness of 75 Shore A to 70 Shore D, and with a softening temperature Tsof of 90° C. to 150° C. at an E′-modulus of 2 MPa (measured according to the DMS-method), which is a reaction product of an aliphatic diisocyanate, at least one Zerewitinoff-active polyol with on average at least 1.8 to not more than 3.0 Zerewitinoff-active hydrogen atoms and with a number-average molecular weight of 600 to 10,000 g/mol and at least one Zerewitinoff-active polyol with an average at least 1.8 to not more than 3.0 Zerewitinoff-active hydrogen atoms and with a number-average molecular weight of 60 to 500 g/mol as a chain lengthener, the molar ratio of the NCO groups of the aliphatic diisocyanate to the OH groups of the chain lengthener and the polyol being 0.85 to 1.2,
• wherein said process comprises the step of producing the photovoltaic module in a vacuum sheet laminator or in a roller laminator.