Heat-shrinkable polyester film and package

A heat-shrinkable polyester film which satisfies the following requirements (1) to (4):

• (1) a hot-water shrinkage of 50% or more in a main shrinkage direction of the film when treated for 10 seconds in hot water of 98° C.;
• (2) when samples are taken at every 100 mm in a width direction of the film, and hot-water shrinkages in a direction orthogonal to the main shrinkage direction of the film are determined for all the samples when treated for 10 seconds in hot water of 98° C., a variation of the hot-water shrinkages is 5% or less;
• (3) an absolute value of a molecular orientation angle is 15 degrees or less;
• and
• (4) a refractive index difference represented by the following equation is 0.06 or more:
• Refractive index difference=(Refractive index in the main shrinkage direction)−(Refractive index in a direction orthogonal to the main shrinkage direction),
• wherein the heat-shrinkage polyester film is prepared from a polyester raw material resin comprising
• (A) 50-90 mol % of an ethylene terephthalate unit in 100 mol % of constituent units of a polyester,
• (B) diol components constituting the polyester include at least one selected from an aliphatic diol, an alicyclic diol, and an aromatic diol, and
• (C) 2-50 mol % of an amorphous monomer component in 100 mol % of a polyhydric alcohol component or in 100 mol % of a polybasic carboxylic acid component in the whole polyester resin,
• wherein the amorphous monomer component is selected from neopentyl glycol, 1,4-cyclohexanedimethanol, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-isopropyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, hexanediol, and combinations thereof, and
• wherein the polyester raw material resin does not contain polybasic carboxylic acids of tribasic or more,
• wherein the polyester film is obtained by uniaxial drawing 2.5 times or more and 7 times or less in the longitudinal direction,
• wherein the polyester film has a main shrinkage direction in a longitudinal direction of the film, and
• wherein a cumulative drawing distance of a drawing distance at a first stage and a drawing distance at a second stage in the preparation of the polyester film is 200 mm or less.