Heat-shrinkable polyester film

Patent metadata

Field	Value
Publication number	US-10189962-B2
Application number	US-201515116759-A
Country	US
Kind code	B2
Filing date	Jan 23, 2015
Priority date	Feb 4, 2014
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A heat-shrinkable polyester film comprising ethylene terephthalate as a main component, containing not less than 0 mol % and not more than 5 mol % of a monomer component capable of serving as an amorphous component relative to the total of a polyester resin component, and having a main shrinkage direction in a lengthwise direction, wherein the heat-shrinkable polyester film satisfies heat shrinkage characteristics of the width direction and the lengthwise direction and the molecular orientation angle difference which is a difference between a molecular orientation angle of an edge of one end in the width direction and a molecular orientation angle of an edge of the other end.

First claim

The invention claimed is:

1. A heat-shrinkable polyester film comprising ethylene terephthalate as a main component, containing not less than 0 mol % and not more than 5 mol % of a monomer component capable of serving as an amorphous component relative to the total of a polyester resin component, and having a main shrinkage direction in a lengthwise direction, wherein the heat-shrinkable polyester film satisfies the following requirements (1) to (3):
(1) the heat-shrinkable polyester film has a hot-water heat shrinkage rate in the lengthwise direction of not less than 15% and not more than 60% when being treated in hot water at 90° C. for 10 seconds;
(2) the heat-shrinkable polyester film has a hot-water heat shrinkage rate in a width direction orthogonal to the lengthwise direction of not less than −10% and not more than 10% when being treated in hot water at 90° C. for 10 seconds; and
(3) the heat-shrinkable polyester film has an orientation distortion index that is a molecular orientation angle difference, the difference being a difference between a molecular orientation angle of an edge of one end in the width direction and a molecular orientation angle of an edge of the other end, per 1 m of the film of not more than 15°/m.

2. The heat-shrinkable polyester film according to claim 1 , wherein the heat-shrinkable polyester film has, in a surface thereof, not more than 100 flaws/m 2 with a depth of not less than 1 μm and a length of not less than 3 mm.

3. The heat-shrinkable polyester film according to claim 1 , wherein a thickness unevenness in the lengthwise direction of the heat-shrinkable polyester film is not more than 10%.

4. The heat-shrinkable polyester film according to claim 1 , wherein the heat-shrinkable polyester film has a tensile strength at break in the width direction orthogonal to the main shrinkage direction of not less than 80 MPa and not more than 200 MPa.

5. The heat-shrinkable polyester film obtained by stretching an unstretched film in a width direction and thereafter stretching the film in a lengthwise direction, and satisfying claim 1 , wherein the heat-shrinkable polyester film is stretched in the lengthwise direction without using a roll heated to a temperature not less than Tg of the film.

6. A package obtained by using the heat-shrinkable polyester film according to claim 1 as a base material for a label or a banding film, wherein the label or the banding film is covered on at least a portion of an outer circumference and heat-shrunk.

Assignees

• Toyo Boseki

Inventors

• Inoue Masafumi
• Haruta Masayuki

Classifications

• B29K2067/003

  PET, i.e. poylethylene terephthalate · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• B32B37/144

  using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding (constructional features for tensioning B32B38/1825) · CPC title

• B29C63/423

  specially applied to the mass-production of externally coated articles, e.g. bottles · CPC title

• B29L2031/712

  Containers; Packaging elements or accessories, Packages (closures therefor B29L2031/56; ink or toner cartridges B29L2031/7678; squeeze tubes B29L2023/20; suitcases B29L2031/7418) · CPC title