RECYCLED PET FILM MANUFACTURED USING RECYCLED CHIPS
A recycled PET film according to the present invention can have significantly low yellowing and color difference values compared to conventional recycled PET films due to the inclusion of a complementary colorant containing a glycerin-based compound, and at the same time satisfy breaking strength and thermal shrinkage levels to replace a new PET material.
1 . A recycled polyethylene terephthalate (PET) film comprising:
waste PET and virgin PET as PET resin components; and
a complementary color agent containing a glycerin-based compound represented by Formula 1 below,
wherein, in the recycled PET film, yellowing resistance is in a range of 5% to 10%, a color difference value L is in a range of 59 to 70, and a color difference value b is 5 or less, wherein the yellowing resistance is measured according to ASTM D1925 and the color differences are measured according to ASTM E313:
wherein, in Formula 1, R 1 , R 2 , and R 3 are each independently straight or branched C 1 -C 20 alkyl or straight or branched C 1 -C 20 unsaturated alkyl.
2 . The recycled PET film of claim 1 , wherein the complementary color agent comprises an organic compound represented by Formula 2 below, an organic compound represented by Formula 3 below, or a mixture thereof:
wherein, in Formula 2, R 4 and R 5 are each independently straight or branched C 1 -C 20 alkyl or straight or branched C 1 -C 20 unsaturated alkyl, and
wherein, in Formula 3, R 6 and R 7 are each independently straight or branched C 1 -C 20 alkyl or straight or branched C 1 -C 20 unsaturated alkyl.
3 . The recycled PET film of claim 1 , wherein the recycled PET film comprises the complementary color agent in a range of 5 ppm to 200 ppm.
4 . The recycled PET film of claim 1 , wherein, in Formulas 1 to 3, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7 are each independently straight or branched C 1 -C 12 alkyl or straight or branched C 1 -C 12 unsaturated alkyl.
5 . The recycled PET film of claim 1 , wherein the recycled PET film comprises metal ions in a range of 10 ppm to 200 ppm, wherein the metal ions are derived from a virgin chip prepared to comprise a molding modifier.
6 . The recycled PET film of claim 5 , wherein the recycled PET film satisfies Expressions 1 to 3 below:
10
≤
[
Mg
]
≤
100
[
Expression
1
]
0.1
≤
[
Na
]
≤
10
[
Expression
2
]
1
≤
[
P
]
≤
5
0
[
Expression
3
]
(wherein, in Expressions 1 to 3,
[Mg] is a concentration (ppm) of magnesium ions contained in the recycled PET film,
[Na] is a concentration (ppm) of sodium ions contained in the recycled PET film, and
[P] is a concentration (ppm) of phosphorus ions contained in the recycled PET film.)
7 . The recycled PET film of claim 1 , wherein the recycled PET film comprises an antiblocking agent in a range of 300 ppm to 1,000 ppm.
8 . The recycled PET film of claim 1 , wherein the recycled PET film has a breaking strength measured according to ASTM D882 is in a range of 10 kgf/mm 2 to 30 kgf/mm 2 in both of a machine direction (MD) and a transverse direction (TD).
9 . The recycled PET film of claim 1 , wherein the recycled PET film has a heat shrinkage ratio of 5% or less in an MD and 1% or less in a TD at a temperature of 200° C.
10 . The recycled PET film of claim 1 , wherein the recycled PET film comprises the waste PET in a range of 30 wt % to 95 wt % and the virgin PET in a range of 5 wt % to 70 wt %.
11 . A method of preparing a recycled polyethylene terephthalate (PET) film, the method comprising:
preparing a recycled chip by including waste PET;
preparing a virgin chip by including virgin PET; and
preparing a recycled PET film by including the recycled chip, the virgin chip, and a glycerin-based compound represented by Formula 1:
wherein, in Formula 1, R 1 , R 2 , and R 3 are each independently straight or branched C 1 -C 20 alkyl or straight or branched C 1 -C 20 unsaturated alkyl.
12 . The method of claim 11 , wherein in the preparing of the recycled PET film, the recycled PET film comprises the recycled chip in a range of 30 wt % to 95 wt % and the virgin chip in a range of 5 wt % to 70 wt %.
13 . The method of claim 11 , wherein the virgin chip is prepared by including a molding modifier in a range of 150 ppm to 14,000 ppm.
14 . The method of claim 11 , wherein the virgin chip is prepared by including an antiblocking agent in a range of 150 ppm to 20,000 ppm.