Laminated film for bonding and light-transmitting laminate comprising same

A laminated film for bonding comprising:

• a first skin layer comprising a first polyvinyl acetal resin and a first plasticizer;
• a core layer disposed on the first skin layer and comprising a second polyvinyl acetal rein and a second plasticizer;
• and
• a second skin layer disposed on the core layer and comprising a third polyvinyl acetal resin and a third plasticizer,
• wherein the core layer comprises a refractive index regulator comprising a metal salt,
• wherein a refractive index of the metal salt is higher than a refractive index of the second plasticizer, and
• wherein the metal salt is a compound indicated by the following Formula 1:
• Mn·Xm [Formula 1]
• in the Formula 1, M is magnesium (Mg), calcium (Ca), sodium (Na), or potassium (K), X is SO4, or NO3, and n and m are integers of 1 or 2, respectively.