Polyester film

Patent metadata

Field	Value
Publication number	US-9987865-B2
Application number	US-201515316042-A
Country	US
Kind code	B2
Filing date	Jun 9, 2015
Priority date	Jun 19, 2014
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A polyester film has a wax on a surface of one side of the film and is a polyester film in which this wax is dispersed in the form of islands on the surface of the film, and a filling factor of the wax in the film surface is 20 to 45%, and, as for a number of islands of the wax dispersed in the form of islands and each of which has an area of 200 μm 2 or larger, there is one or less/10000 μm 2 .

First claim

The invention claimed is:

1. A polyester film containing particles that form protrusions on a surface of one side of the film and having a wax on the surface having the protrusions, wherein a number of the protrusions (SPc) on the surface is 300 to 500/0.2 mm 2 , the wax is dispersed in a form of islands on the surface of the film, the particles are contained in the islands, a filling factor of the wax in the film surface is 20 to 45%, and, a number of islands of the wax dispersed in the form of islands and each of which has an area of 200 μm 2 or larger is one or less /10000 μm 2 .

2. The polyester film according to claim 1 , wherein the polyester film contains the particles in an amount of 0.4 to 1.0 wt % relative to an entire polyester resin composition that constitutes the film and a thickness of the film is 2 to 20 μm.

3. An ink ribbon for thermal transfer comprising the polyester film according to claim 1 .

4. A thermal transfer ink ribbon in which a one-side surface of the polyester film according to claim 1 is provided with a transfer layer and a surface opposite to the transfer layer is provided with a slipping layer comprising the wax.

5. A process of producing the polyester film described in claim 1 comprising forming a polyester sheet under at least one of conditions (a) to (d):
(a) an amount of particles contained in the sheet is 0.4 to 1.0 wt %,
(b) subjecting a surface of the sheet to an electric discharge treatment under a specific condition, and applying a coating liquid containing the wax to the sheet to form the film, wherein the specific condition is, following a corona electric discharge treatment on a surface of a machine direction of stretched polyester sheet which is to be coated with the coating liquid containing the wax, under the conditions: an electric discharge density of 0.5×10 4 W/m 2 to 2.0×10 4 W/m 2 and a treatment time of 0.01 to 0.05 seconds,
(c) wax concentration (solid content concentration) in the coating liquid is 0.3 wt % to 1.0 wt %, and
(d) applying the coating selected from a bar coating method or a gravure coating method, to thereby produce the film.

6. A process of producing the polyester film described in claim 2 comprising forming a polyester sheet under at least one of conditions (a) to (d):
(a) an amount of particles contained in the sheet is 0.4 to 1.0 wt %,
(b) subjecting a surface of the sheet to an electric discharge treatment under a specific condition, and applying a coating liquid containing the wax to the sheet to form the film, wherein the specific condition is, following a corona electric discharge treatment on a surface of a machine direction of stretched polyester sheet which is to be coated with the coating liquid containing the wax, under the conditions: an electric discharge density of 0.5×10 4 W/m 2 to 2.0×10 4 W/m 2 and a treatment time of 0.01 to 0.05 seconds,
(c) wax concentration (solid content concentration) in the coating liquid is 0.3 wt % to 1.0 wt %, and
(d) applying the coating selected from a bar coating method or a gravure coating method, to thereby produce the film.

Assignees

• Toray Industries

Inventors

• Hayano Tomoko
• Takahashi Jun

Classifications

• B41J31/05 Primary

  Ink ribbons having coatings other than impression-material coatings · CPC title

• C08J7/04 Primary

  Coating · CPC title

• B41M5/40

  characterised by the base {backcoat}, intermediate, or covering layers, {e.g. for thermal transfer dye-donor or dye-receiver sheets}; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography {(macromolecular ink- or dye-receptive coatings B41M5/52)} · CPC title

• B41M5/423

  characterised by non-macromolecular compounds, e.g. waxes · CPC title

• B41M2205/30

  Thermal donors, e.g. thermal ribbons · CPC title