Exterior edge seal for a module
An external edge seal is used at the exterior edges of different modules to decrease the permeation of moisture and reactive gas to lengthen the life span of the modules. The sealed module can be a photovoltaic module, an insulating glass unit, a screen, a dynamic glazing product, a switchable window, an electrochromic window, a thin-film transistor, or other modules using items between substrates. The edge seal includes a desiccated adhesive carried by a barrier film to form a tape. The vapor barrier can be placed along the edge of a sealed module or around the edge and against portions of the outer substrate surfaces of the sealed module to provide a desiccated seal that provides or lengthens the desiccated path that moisture vapor must follow before permeating the inner space of the sealed module.
1 . A sealed module comprising:
a first substrate having an outer surface and an outer perimeter edge;
a second substrate having an outer surface and an outer perimeter edge;
a photovoltaic material between the first and second substrates;
the first substrate being spaced from the second substrate;
an external edge seal having a barrier film and a desiccated adhesive carried by the barrier film; the barrier film having a very low MVTR;
the desiccated adhesive of the external edge seal extending around edge portions of the first and second substrates with the desiccated adhesive in contact with the outer surface of the first substrate, the outer perimeter edge of the first substrate, the outer perimeter edge of the second substrate, and the outer surface of the second substrate, wherein the desiccated adhesive extends continuously from the outer surface of the first substrate to the outer surface of the second substrate; and
the desiccated adhesive of the external edge seal increasing the time for moisture to penetrate the module and reach the photovoltaic material.
2 . The module of claim 1 , further comprising an internal edge seal between the first and second substrates; the desiccated adhesive being in contact with the internal edge seal.
3 . The module of claim 2 , wherein the internal edge seal is desiccated.
4 . The module of claim 1 , wherein desiccated adhesive includes an isobutylene-based polymer and a desiccant at a concentration of less than 20 weight percent.
5 . The module of claim 4 , wherein the desiccant is a zeolite molecular sieve.