Polyester film and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-11572449-B2
Application number	US-202117195558-A
Country	US
Kind code	B2
Filing date	Mar 8, 2021
Priority date	Apr 28, 2020
Publication date	Feb 7, 2023
Grant date	Feb 7, 2023

Abstract

A polyester film and a method for manufacturing the same are provided. The polyester film includes a physically recycled polyester resin and a chemically recycled polyester resin. The physically recycled polyester resin is formed by a plurality of physically recycled polyester chips. The chemically recycled polyester resin is formed by a plurality of chemically recycled polyester chips and mixed with the physically recycled polyester resin. The plurality of chemically recycled polyester chips further includes chemically recycled electrostatic pinning polyester chips. The chemically recycled electrostatic pinning polyester chips contain electrostatic pinning additives, and the electrostatic pinning additives are metal salts. Expressed in percent by weight based on a total weight of the polyester film, a content of the electrostatic pinning additives in the polyester film is between 0.005% and 0.1% by weight.

First claim

What is claimed is:

1. A method for manufacturing a polyester film, which is used to recycle and reuse a recycled polyester material, the method comprising:
physically reproducing a part of the recycled polyester material and granulating the same to obtain a plurality of physically recycled polyester chips;
chemically reproducing another part of the recycled polyester material and granulating the same to obtain a plurality of chemically recycled polyester chips, wherein the plurality of chemically recycled polyester chips further includes chemically recycled electrostatic pinning polyester chips, and wherein the chemically recycled electrostatic pinning polyester chips contain at least one kind of electrostatic pinning additives, and the electrostatic pinning additives are metal salts; and
mixing the plurality of physically recycled polyester chips and the plurality of chemically recycled polyester chips, and melt extruding the same to form the polyester film;
wherein, based on 100 parts by weight of a total content of the polyester chips, a content of the chemically recycled electrostatic pinning polyester chips of the plurality of chemically recycled polyester chips is between 5 and 35 parts by weight.

2. The method according to claim 1 , wherein in the polyester film, the plurality of physically recycled polyester chips form a physically recycled polyester resin, and the plurality of chemically recycled polyester chips form a chemically recycled polyester resin that is mixed with the physically recycled polyester resin; wherein, based on 100 parts by weight of the total content of the polyester chips, a content of the plurality of physically recycled polyester chips is between 50 and 95 parts by weight, a content of the plurality of chemically recycled polyester chips is between 1 and 40 parts by weight, and a total content of the plurality of physically recycled polyester chips and the plurality of chemically recycled polyester chips is between 55 and 100 parts by weight.

3. The method according to claim 1 , wherein the step of chemically reproducing another part of the recycled polyester material further includes: depolymerizing the recycled polyester material to obtain a raw material mixture, and repolymerizing the raw material mixture and granulating the same, thereby obtaining the plurality of chemically recycled polyester chips.

4. The method according to claim 3 , wherein the step of repolymerizing the raw material mixture further includes: adding the electrostatic pinning additives to a part of the raw material mixture, and then repolymerizing the raw material mixture that is added with the electrostatic pinning additives and granulating the same, thereby obtaining the chemically recycled electrostatic pinning polyester chips.

5. The method according to claim 4 , wherein a content of the electrostatic pinning additives in the chemically recycled electrostatic pinning polyester chips is between 0.01% and 0.3% by weight, so that a content of the electrostatic pinning additives in the polyester film is between 0.005% and 0.1% by weight.

6. The method according to claim 3 , wherein the step of repolymerizing the raw material mixture further includes: adding a slipping agent to a part of the raw material mixture, and then repolymerizing the raw material mixture that is added with the slipping agent and granulating the same to obtain chemically recycled slipping polyester chips; wherein the slipping agent is at least one selected from a material group consisting of silicon dioxide particles, calcium carbonate particles, barium sulfate particles, polystyrene particles, silica gel particles, and acrylic particles; wherein, based on 100 parts by weight of the total content of the polyester chips, a content of the chemically recycled slipping polyester chips is between 5 and 10 parts by weight.

7. The method according to claim 6 , wherein a content of the slipping agent in the chemically recycled slipping polyester chips is between 0.1% and 20% by weight, so that a content of the slipping agent in the polyester film is between 0.01% and 2% by weight; wherein a particle size of the slipping agent is less than 2 micrometers, and the polyester film does not include any color pigment, such that the polyester film has a transparency of not less than 85%, and a haze of not greater than 5%.

8. The method according to claim 1 , wherein the plurality of physically recycled polyester chips and the plurality of chemically recycled polyester chips are both obtained through recycling, reusing, and granulation of the recycled polyester material; wherein the recycled polyester material is recycled PET (r-PET) bottle chips.

9. The method according to claim 8 , wherein a polyester component of the recycled PET bottle chips includes isophthalic acid (IPA) serving as a dibasic acid unit, so that the polyester film that is finally formed also contains the isophthalic acid (IPA); wherein, expressed in mole percent based on a total weight of the polyester film, a content of the isophthalic acid in the polyester film is between 0.5 mol % and 5 mol %.

10. The method according to claim 8 , wherein a polyester component of the recycled PET bottle chips includes biomass-derived ethylene glycol serving as a diol unit, so that the polyester film that is finally formed also contains the biomass-derived ethylene glycol; wherein, expressed in percent by weight based on the total weight of the polyester film, a content of the biomass-derived ethylene glycol in the polyester film is between 1% and 25% by weight; wherein a content of carbon derived from the biomass as measured by carbon-14 dating is not greater than 5% based on a total carbon content of the polyester film.

11. The method according to claim 8 , wherein a polyester component of the recycled PET bottle chips includes a metal catalyst, so that the polyester film that is finally formed also contains the metal catalyst, wherein the metal catalyst is at least one selected from a material group consisting of antimony (Sb), germanium (Ge), and titanium (Ti); wherein, when expressed in percent by weight based on the total weight of the polyester film, a content of the metal catalyst in the polyester film is between 0.0003% and 0.04% by weight.

12. The method according to claim 1 , wherein a concentration of cyclic oligomers generated in the step of physically reproducing the part of the recycled polyester material is less than a concentration of cyclic oligomers generated in the step of chemically reproducing another part of the recycled polyester material.

13. The method according to claim 1 , wherein the step of chemically reproducing another part of the recycled polyester material further includes: using an ethylene glycol depolymerization solution to depolymerize the recycled polyester material, thereby obtaining the raw material mixture, and then the plurality of physically recycled polyester chips are mixed with the plurality of chemically recycled polyester chips to decrease a concentration of diethylene glycol in the polyester film.

14. A polyester film, comprising:
a physically recycled polyester resin formed by a plurality of physically recycled polyester chips; and
a chemically recycled polyester resin formed by a plurality of chemically recycled polyester chips and mixed with the physically recycled polyester resin, wherein the plurality of chemically recycled polyester chips further includes chemically recycled electrostatic pinning polyester chips, and wherein the chemically recycled electrostatic pinning polyester chips contain at least one kind of electrostatic pinning additives, and the electrostatic pinning additiv

Assignees

• Nanya Plastics Corp

Inventors

• Liao Te-Chao
• Yang Wen-Cheng
• Yang Chun-Cheng
• HSIAO Chia-Yen
• Hsieh Yu-Chi

Classifications

• C08J2367/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) · CPC title

• B29K2067/00

  Use of polyesters {or derivatives thereof}, as moulding material · CPC title

• Y02P20/143

  the feedstock being recycled material, e.g. plastics · CPC title

• C08J11/24

  containing hydroxyl groups · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title