Biaxially oriented pet film and manufacturing method thereof

Abstract

A biaxially oriented polyester film is provided, comprising a polyester material, a metal catalyst material, and a crystallization inhibitor material, such that, when the biaxially oriented polyester film is analyzed by differential scanning calorimetry (DSC) at cooling rates of 20°C / min and 40°C / min from a molten state, the difference between a first recrystallization temperature and a second recrystallization temperature is greater than 15°C and less than or equal to 23°C. A method for manufacturing the biaxially oriented polyester film is also provided.

Claims

1. A biaxially oriented polyester film made of a polyester resin mixture, wherein the polyester resin mixture comprises a polyester material, a metal catalyst material, and a crystallization inhibitor material, such that, when the biaxially oriented polyester film is analyzed by differential scanning calorimetry, the difference between a first recrystallization temperature and a second recrystallization temperature observed when cooled from a molten state at cooling rates of 20°C / min and 40°C / min, respectively, is greater than 15°C and less than or equal to 23°C, wherein the metal catalyst material comprises antimony, germanium, titanium, cobalt, magnesium, lithium, sodium, potassium, or combinations thereof, and the crystallization inhibitor material comprises isophthalic acid, neopentyl glycol, diethylene glycol, 1,4-cyclohexanediethanol, or combinations thereof.

2. The biaxially oriented polyester film as claimed in claim 1, wherein the content of the metal catalyst material is between 0.3 ppm / mol% and 40 ppm / mol% of the crystallization inhibitory material relative to the molar percentage concentration of the crystallization inhibitory material is between 2 mol% and 8 mol% of the molar percentage concentration of the polyester resin mixture.

3. The biaxially oriented polyester film as claimed in claim 1, wherein the polyester material comprises recycled polyester material, virgin polyester material, or a combination thereof.

4. The biaxially oriented polyester film as claimed in claim 1, wherein the first recrystallization temperature is greater than 170°C.

5. The biaxially oriented polyester film as claimed in claim 1, wherein the second recrystallization temperature is between 150°C and 175°C.

6. The biaxially oriented polyester film as claimed in claim 1, wherein the thickness of the biaxially oriented polyester film is greater than 10 micrometers.

7. A method for manufacturing a biaxially oriented polyester film, comprising: Provide polyester granules, wherein the polyester granules comprise at least chemically recycled polyester granules, and the chemically recycled polyester granules have a metal catalyst material and a crystallization inhibitor material, wherein the metal catalyst material comprises antimony, germanium, titanium, cobalt, magnesium, lithium, sodium, potassium, or combinations thereof, and the crystallization inhibitor material comprises isophthalic acid, neopentyl glycol, diethylene glycol, 1,4-cyclohexanediethanol, or combinations thereof; melt-extrude the polyester granules to form an unstretched sheet, wherein the molten polyester granules are a polyester resin mixture; and biaxially stretch the sheet to form the biaxially stretched polyester film, wherein the biaxially stretched polyester film, when analyzed by differential scanning calorimetry, shows a difference between a first recrystallization temperature and a second recrystallization temperature greater than 15°C and less than or equal to 23°C when cooled from the molten state at cooling rates of 20°C / min and 40°C / min, respectively.

8. A method for manufacturing a biaxially oriented polyester film as claimed in claim 7, wherein the polyester pellets further comprise one or both of virgin polyester pellets and physically recycled polyester pellets.

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