Highly heat-resistant polyester sheet

Patent metadata

Field	Value
Publication number	US-10420209-B2
Application number	US-201515507807-A
Country	US
Kind code	B2
Filing date	Aug 24, 2015
Priority date	Sep 2, 2014
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

The polyester sheet in accordance with an aspect of the present invention contains crystals of polyester which is a polycondensate of polyvalent carboxylic acid and polyalcohol. The polyester sheet contains nano-oriented crystals which contain crystals of polyester in each of which a polymer chain is highly oriented and each of which has a crystal size of 50 nm or less. A heatproof temperature of the polyester sheet is higher than a temperature that is lower than an equilibrium melting point of the polyester by 80° C., and a melting point of the polyester sheet is higher than a temperature that is lower than the equilibrium melting point of the polyester by 40° C.

First claim

The invention claimed is:

1. A polyester sheet consisting of polyester, wherein the polyester sheet contains crystals of polyester which is a polycondensate of polyvalent carboxylic acid and polyalcohol,
the crystals being nano-oriented crystals including crystals of polyester in each of which a polymer molecular chain is oriented and each of which has a crystal size of 50 nm or less, wherein the polyester sheet contains the nano-oriented crystals as a main component,
a heatproof temperature of said polyester sheet being higher than a temperature that is lower than an equilibrium melting point of the polyester by 80° C.

2. The polyester sheet as set forth in claim 1 , wherein:
said polyester sheet has a melting point higher than a temperature that is lower than the equilibrium melting point of the polyester by 40° C.

3. The polyester sheet as set forth in claim 1 , wherein:
the nano-oriented crystals have a structure in which spindle-shaped crystals are arranged in such a manner as to be tied in a row.

4. The polyester sheet as set forth in claim 1 , wherein:
the heatproof temperature of said polyester sheet is 200° C. or higher.

5. The polyester sheet as set forth in claim 1 , wherein:
the polyester is polyethylene terephthalate or polyethylene naphthalene dicarboxylate.

6. The polyester sheet as set forth in claim 1 , wherein:
the polyester is polyethylene terephthalate.

7. The polyester sheet as set forth in claim 6 , wherein:
a density of said polyester sheet is 1.4 g/cm 3 or more.

8. The polyester sheet as set forth in claim 1 , wherein:
a crystal form of the nano-oriented crystals of the polyester is monoclinic.

9. The polyester sheet as set forth in claim 1 , wherein:
said polyester sheet is used in high-temperature processing at a temperature higher than 200° C.

10. The polyester sheet as set forth in claim 9 , wherein:
said polyester sheet is used as a base material of a laminated body including an electrically conductive transparent layer.

11. The polyester sheet as set forth in claim 9 , wherein:
said polyester sheet is used as a base material of a flexible circuit board.

12. A flexible circuit board comprising a polyester sheet recited in claim 11 as a base material.

13. The polyester sheet as set forth in claim 1 , wherein the polyester sheet contains the nano-oriented crystals in an amount of 60% or higher.

Assignees

• Univ Hiroshima
• Teijin Film Solutions Ltd

Inventors

• Hikosaka Masamichi
• Okada Kiyoka
• Tanaka Yoshitaka

Classifications

• B32B2307/704

  Crystalline · CPC title

• B29C48/88

  Thermal treatment of the stream of extruded material, e.g. cooling · CPC title

• H05K2201/0145

  Polyester, e.g. polyethylene terephthalate [PET], polyethylene naphthalate [PEN] · CPC title

• B32B2367/00

  Polyesters, e.g. PET, i.e. polyethylene terephthalate · CPC title

• B32B27/36

  comprising polyesters · CPC title