Polyester single layer film
A polyester single layer film according to an embodiment of the present invention has low haze and low oligomer characteristics, has a more bluish color coordinate, and has a low inorganic metal content. Accordingly, the polyester single layer film may be used as a base film of a heat-resistant protective film and a light-scattering preventive film, as well as an ITO and non-ITO base film (for Ag nanowire, or the like) used in recent touch panels. In addition, since the transmittance at a wavelength of 550 nm is relatively high due to less impurity, the polyester single layer film may be used as a base film of a prism for a backlight unit (BLU) and a diffusion sheet.
1. A polyester single layer film comprising a polyester resin prepared by using a germanium compound as a catalyst, wherein the polyester single layer film has a haze of 0.5% or less and shows a haze change rate of 1% or less when heat-treated at 150° C. for 3 hours, and
wherein the polyester single layer film comprises an inorganic metal of 100 ppm or less, and does not comprise an applicator component selected from the group consisting of magnesium and potassium.
2. The polyester single layer film of claim 1 , wherein the inorganic metal does not comprise silicon.
3. The polyester single layer film of claim 1 , wherein the polyester single layer film shows a haze change rate of 2% or less when heat-treated at 150° C. for 9 hours.
4. The polyester single layer film of claim 1 , wherein the polyester resin is polyethylene terephthalate.
5. The polyester single layer film of claim 1 , wherein the polyester resin has an intrinsic viscosity (IV) of 0.6 to 0.8 dl/gr.
6. The polyester single layer film of claim 1 , wherein the polyester single layer film comprises a total oligomer in an amount of 0.5 to 2.2% by weight when measured by being dissolved in trifluoroacetic acid.
7. A conductive film, comprising:
the polyester single layer film according to claim 1 ; and
an indium tin oxide (ITO)-based conductive layer, which is formed on one side of the polyester single layer film, in a laminated form,
wherein the conducive layer does not comprise a hard coating layer.
8. A heat-resistant protective film comprising the polyester single layer film according to claim 1 .
9. A light-scattering preventive film comprising the polyester single layer film according to claim 1 .
10. An optical sheet comprising the polyester single layer film according to claim 1 .