The present invention relates to a resin composition which has a low
viscosity (at 25˚C) of not more than 1300mPa·s and a relatively high liquid
refractive index of at least 1.50, which is used to seal a surface of an organic electroluminescent (EL) element, and with which a cured product exhibiting excellent visible
light transmission, excellent light resistance, a high Tg, and a low water vapour
transmission rate can be obtained. The resin composition has a
viscosity measured at 25˚C of not more than 1300mPa·s, and includes an aromatic compound (A) and a
cyclic compound (B). Aromatic compound (A) has an oxetanyl group or an
epoxy group, and has at least one skeleton selected from the group consisting of: a skeleton of
biphenyl,
bisphenol A,
bisphenol F,
bisphenol S, or the like represented by formula (A-A) […]; a
phenylene skeleton which may be substituted with a C1-4
alkyl group, and which is represented by formula (A-B) […]; an
anthracene skeleton; and a
phenanthrene skeleton.
Cyclic compound (B) has an oxetanyl group or an
epoxy group, and satisfies the following conditions (conditions for
cyclic compound (B): that the ring in
cyclic compound (B) be an aromatic ring, an aliphatic ring, or a heterocycle; in cases when the ring is (a) an aromatic ring, that the cyclic compound have an oxetanyl group or an
epoxy group, and an aromatic ring having a structure different to that of the compound used as aromatic compound (A); and, in cases when the ring is (b) an aliphatic ring, that the cyclic compound be either an alicyclic epoxy resin, or, a cyclic compound having an oxetanyl group or an epoxy group, and a cycloalkylene skeleton or an alicyclic
hydrocarbon skeleton having a cross-linking structure).