Biaxially drawn colored polyester film for laminating metal sheet

Patent metadata

Field	Value
Publication number	US-11072149-B2
Application number	US-201816219369-A
Country	US
Kind code	B2
Filing date	Dec 13, 2018
Priority date	Dec 15, 2017
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

A biaxially drawn colored polyester film includes at least two layers: a surface layer (layer A) mainly composed of polyester having a melting point TmA of 230 to 260° C. and modified polyolefin wax, layer A having a polymer component with intrinsic viscosity of 0.46 or more, the modified polyolefin wax with an amount of 0.2 wt % or more based on the weight of the composition, coloring pigment with an amount of 10 wt % or less, and a water contact angle of less than 70° on an outer surface; and a substrate layer (layer B) mainly composed of polyester having a melting point TmB of 230 to 260° C. and coloring pigment, layer B having a polymer component with intrinsic viscosity of 0.46 or more and the coloring pigment with an amount of more than 10 wt % and 50 wt % or less; wherein |TmB−TmA| is 4° C. or less.

First claim

The invention claimed is:

1. A biaxially drawn colored polyester film for laminating and forming metal sheet, comprising at least two layers:
a surface layer (layer A) mainly composed of a polyester having a melting point of 230 to 260° C. and modified polyolefin wax, layer A having a polymer component with intrinsic viscosity of 0.46 or more, the modified polyolefin wax with an amount of 0.2 to 2.0 wt % based on the weight of the composition, a coloring pigment with an amount of 10 wt % or less, and a water contact angle on an outer surface of less than 70°; and
a substrate layer (layer B) mainly composed of a polyester having a melting point of 230 to 260° C. and a coloring pigment, layer B having a polymer component with intrinsic viscosity of 0.46 or more and the coloring pigment with an amount of more than 10 wt % and 50 wt % or less;
wherein the melting points of the polyesters of layer A and layer B satisfy the following expression (1):
|Tm B −Tm A |≤4° C.   (1)

wherein TmA represents the melting point of the polyester of layer A, and
TmB represents the melting point of the polyester of layer B.

2. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 1 , wherein the polyester constituting layer B is a copolyester having a melting point of 230 to 255° C.

3. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 2 , wherein the polyester constituting layer A is a copolyester having a melting point of 230 to 255° C.

4. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 1 , wherein the polyester constituting layer A is a copolyester having a melting point of 230 to 255° C.

5. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 1 , wherein the modified polyolefin wax contains at least one selected from the group consisting of acid-modified polypropylene wax, acid-modified polyethylene wax, oxidized polypropylene wax, and oxidized polyethylene wax.

6. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 1 , wherein the film is laminated on a surface of a metal sheet that will become the outer surface of a container.

7. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 1 , wherein the polyester constituting layer A is a first isophthalic acid-copolymerized polyethylene terephthalate having a melting point of 230 to 255° C., and the polyester constituting layer B is a second isophthalic acid-copolymerized polyethylene terephthalate having a melting point of 230 to 255° C.

8. The biaxially drawn colored polyester film for laminating and forming metal sheet according to claim 1 , wherein the melting point of the polyester constituting layer A is lower than the melting point of the polyester constituting layer B.

Assignees

• Teijin Film Solutions Ltd
• Toyo Boseki

Inventors

• IYO Naoki
• Yano Shinji

Classifications

• B32B2323/04

  Polyethylene · CPC title

• B32B2307/308

  Heat stability · CPC title

• C08L67/03

  the dicarboxylic acids and dihydroxy compounds having the carboxyl- and the hydroxy groups directly linked to aromatic rings · CPC title

• C08L23/30

  by oxidation · CPC title

• B32B2311/24

  Aluminium · CPC title