Heat shrinkable film and method for reproducing polyester container using same

Patent metadata

Field	Value
Publication number	US-11008434-B2
Application number	US-201916687357-A
Country	US
Kind code	B2
Filing date	Nov 18, 2019
Priority date	Apr 30, 2018
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

Embodiments relate to a heat shrinkable film and a process for regenerating a polyester container using the same. The heat shrinkable film comprises a copolymerized polyester resin comprising a diol component and a dicarboxylic acid component and has a heat shrinkage rate of 30% or more in the main shrinkage direction upon thermal treatment at a temperature of 80° C. for 10 seconds and a melting point of 190° C. or higher as measured by differential scanning calorimetry. It not only solves the environmental problems by improving the recyclability of the polyester container, but also is capable of enhancing the yield and productivity.

First claim

The invention claimed is:

1. A container comprising:
a polyester container, and
a heat shrinkable film, which is provided at the polyester container;
wherein the heat shrinkable film is shrunk by steam or hot air to wrap the outer surface of the polyester container,
wherein the heat shrinkable film comprises a copolymerized polyester resin comprising a diol component and a dicarboxylic acid component and
has a heat shrinkage rate of 30% or more in the main shrinkage direction upon thermal treatment at a temperature of 80° C. for 10 seconds and
a melting point of 190° C. or higher as measured by differential scanning calorimetry,
wherein when a plurality of flakes are thermally treated at a temperature of 200° C. to 220° C. for 60 minutes to 120 minutes, the clumping fraction is 5% or less,
wherein the flakes are formed by crushing the polyester container and the heat shrinkable film.

2. The container of claim 1 , wherein the crystallization temperature of the resin is not measured or is 70° C. to 95° C. by differential scanning calorimetry.

3. The container of claim 1 , wherein the diol component is at least one selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, and cyclohexanedimethanol.

4. The container of claim 1 , wherein the copolymerized polyester resin comprises neopentyl glycol in an amount of 5 to 35% by mole based on the total number of moles of the diol component.

5. The container of claim 1 , wherein the copolymerized polyester resin comprises ethylene glycol in an amount of 55 to 93% by mole based on the total number of moles of the diol component.

6. The container of claim 1 , which has a heat shrinkage rate of 5% to 55% in the main shrinkage direction upon thermal treatment at a temperature of 70° C. for 10 seconds,
wherein the rate of increase in the heat shrinkage rate in the main shrinkage direction in the temperature range of 0.35×Tm° C. to 0.40×Tm° C. is 2.5%/° C. to 4.0%/° C., and
the rate of increase in the heat shrinkage rate in the main shrinkage direction in the temperature range of 0.45: Tm° C. to 0.50: Tm° C. is 0.1%/° C. to 1.0%/° C.

7. A container comprising:
a polyester container, and
a heat shrinkable film, which is provided at the polyester container;
wherein the heat shrinkable film is shrunk by steam or hot air to wrap the outer surface of the polyester container,
wherein the heat shrinkable film comprises a copolymerized polyester resin comprising a diol component and a dicarboxylic acid component and
has a heat shrinkage rate of 30% or more in the main shrinkage direction upon thermal treatment at a temperature of 80° C. for 10 seconds and
wherein the crystallization temperature of the heat shrinkable film is not measured or is 70° C. to 95° C. by differential scanning calorimetry,
wherein when a plurality of flakes are thermally treated at a temperature of 200° C. to 220° C. for 60 minutes to 120 minutes, the clumping fraction is 5% or less,
wherein the flakes are formed by crushing the polyester container and the heat shrinkable film.

8. The container of claim 7 , wherein the heat of crystallization of the heat shrinkable film at the crystallization temperature is not measured or is 0.01 to 50 J/g.

9. The container of claim 7 , which has a heat shrinkage rate of 5% to 55% in the main shrinkage direction upon thermal treatment at a temperature of 70° C. for 10 seconds,
wherein the rate of increase in the heat shrinkage rate in the main shrinkage direction in the temperature range of 0.85×Tc° C. to 1.00×Tc° C. is 2.5%/° C. to 4.0%/° C., and
the rate of increase in the heat shrinkage rate in the main shrinkage direction in the temperature range of 1.12×Tc° C. to 1.27×Tc° C. is 0.11%/° C. to 1.0%/° C.

10. A process for regenerating the container according to claim 1 ;
crushing the polyester container provided with the heat shrinkable film to obtain the flakes; and
thermally treating the flakes to produce regenerated polyester chips,
wherein the flakes comprise first flakes obtained by crushing the container and second flakes obtained by crushing the heat shrinkable film.

11. The process for regenerating a polyester container of claim 10 , wherein the flakes are thermally treated at a temperature of 200° C. to 220° C. for 60 minutes to 120 minutes, and the clumping fraction is 5% or less.

12. A process for regenerating the container according to claim 7 ;
crushing the container provided with the heat shrinkable film to obtain the flakes; and
thermally treating the flakes to produce regenerated polyester chips,
wherein the flakes comprise first flakes obtained by crushing the container and second flakes obtained by crushing the heat shrinkable film.

13. The process for regenerating a polyester container of claim 12 , wherein the flakes are thermally treated at a temperature of 200° C. to 220° C. for 60 minutes to 120 minutes, and the clumping fraction is 5% or less.

Assignees

• Skc Inc
• Skc Co Ltd

Inventors

• Shin Daeyong
• Kim Yongdeuk
• Lee Jung Kyu
• Son Jaehyong
• Jung Eugene

Classifications

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• C08G63/672 Primary

  Dicarboxylic acids and dihydroxy compounds · CPC title

• C08G63/183

  Terephthalic acids · CPC title

• B29B2017/0496

  Pyrolysing the materials · CPC title

• C08J11/12 Primary

  by dry-heat treatment only · CPC title