A sealing material for a solar cell used in a solar power generation system having a system voltage of 600 V or more, the sealing material being constituted of a heat-crosslinking resin composition comprising an ethylene copolymer, a crosslinking agent and a crosslinking aid that comprises a polyfunctional monomer having 4 or more (meth)acryloyl groups in combination with triallyl isocyanurate.
Conventionally, as a sealing material used for a solar power generation element, there has been proposed a resin composition comprising an ethylene copolymer as a base material and an organic peroxide as a crosslinking agent.
TAIC (triallyl isocyanurate) to be used together with the crosslinking agent is a useful crosslinking aid upon obtaining a molded body by curing a crosslinking polymer. In particular, when crosslinking an ethylene-vinyl acetate copolymer with an organic peroxide.
TAIC is essentially required as a crosslinking aid, and is capable of providing a sealing material for a solar cell which has high transparency, adhesive properties, heat resistance and flexibility. Actually, a transparent film comprising a triallyl isocyanurate-polymerized crosslinked product of an ethylene-vinyl acetate copolymer as a main component has been proposed for use in applications such as a sealing material for solar cells.
Meanwhile, in recent years, a large-scale power generation system using a solar cell (mega solar system, etc.) has been used, and therefore the system voltage becomes as high as 600 V or more. With this circumstance, there tends to occur such a problem that a sealing material used for the solar cell must be improved in insulation properties