Polyester film for window attachment, and polyester film layered body for window attachment

A polyester film, comprising:

• a polyester layer (A) containing a halogen-free blue dye and a pigment;
• and
• a polyester layer (B) on one surface of the polyester layer (A),
• wherein the halogen-free blue dye and the pigment are melted and blended with each other prior to formation of the polyester layer (A),
• wherein the pigment is present in the polyester layer (A) in an amount of 0.02 to 0.1% by mass based on a total mass of the polyester layer (A), and
• wherein the halogen-free blue dye and the pigment are prepared in a master batch by melting and mixing a first polyester, the halogen-free blue dye, and the pigment to form the master batch including the pigment in an amount of greater than 0.1% by mass based on a total mass of the master batch, and
• wherein the polyester layer (A) is formed by blending the master batch with a second polyester free of the halogen-free blue dye and the pigment to form a mixture, the mixture including the pigment in an amount of 0.02 to 0.1% by mass based on a total mass of the mixture, and extruding the mixture.