Thermal transfer sheet

Patent metadata

Field	Value
Publication number	US-11279161-B2
Application number	US-201816607422-A
Country	US
Kind code	B2
Filing date	Feb 28, 2018
Priority date	Aug 24, 2017
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

Provided is a thermal transfer sheet having an excellent high-speed transferability and capable of forming images with high fluorescence intensity and abrasion resistance. The thermal transfer sheet of the present invention includes a substrate, a fluorescent layer, and a thermofusible ink layer in this order, in which the fluorescent layer contains a fluorescent material, and a vinyl resin.

First claim

The invention claimed is:

1. A thermal transfer sheet, comprising, in this order:
a substrate;
a fluorescent layer; and
a thermofusible ink layer,
wherein the fluorescent layer contains a fluorescent material, and a vinyl acetate-vinylpyrrolidone copolymer, a first particle, and a second particle that is different from the first particle, and
wherein the first particle is at least one particle selected from the group consisting of a thermocurable resin particle, a (meth)acrylic resin particle, a silicon-containing resin particle, a fluorine-containing resin particle, a silica particle, an alumina particle, a clay particle, a talc particle, a calcium carbonate particle, a barium oxide particle, a zinc oxide particle, a titanium oxide particle and a glass bead.

2. The thermal transfer sheet according to claim 1 , wherein fluorescence intensities A and B satisfy the following formula:
B/A≥ 3,
wherein the fluorescence intensity A is obtained by irradiating the thermal transfer sheet with an ultraviolet light at an excitation wavelength of 365 nm from the side provided with the thermofusible ink layer, where the substrate is arranged at the center; thereby making the fluorescent layer emit a light; and then measuring the fluorescence intensity at 470 nm using a fluorescence spectrophotometer, and
wherein the fluorescence intensity B is obtained by irradiating the thermal transfer sheet with an ultraviolet light at an excitation wavelength of 365 nm from the side not provided with the thermofusible ink layer, where the substrate is arranged at the center; thereby making the fluorescent layer emit a light, and then measuring the fluorescence intensity at 470 nm using a fluorescence spectrophotometer.

3. The thermal transfer sheet according to claim 1 , wherein the fluorescent layer has a thickness of 0.1 μm or more and 1.5 μm or less.

4. The thermal transfer sheet according to claim 1 , wherein the content of the fluorescent material in the fluorescent layer is 0.1% by mass or more and 60% by mass or less.

5. The thermal transfer sheet according to claim 1 , further comprising a peeling layer between the substrate and the fluorescent layer.

6. The thermal transfer sheet according to claim 1 , wherein the first particle is a filler having a melting point of 120° C. or higher.

7. The thermal transfer sheet according to claim 1 , wherein the first particle has a primary particle size of 0.1 μm or more and 2 μm or less.

8. The thermal transfer sheet according to claim 1 , wherein the second particle has a melting point of lower than 120° C.

9. The thermal transfer sheet according to claim 1 , wherein the second particle is wax.

10. The thermal transfer sheet according to claim 1 , wherein the sum of the contents of the first particle and the second particle in the fluorescent layer is 15% by mass or more and 65% by mass or less.

11. The thermal transfer sheet according to claim 5 , wherein the peeling layer contains a vinyl resin.

12. The thermal transfer sheet according to claim 11 , wherein a content of the vinyl resin in the peeling layer is in a range of 2% by mass or more to 25% by mass or less.

13. The thermal transfer sheet according to claim 11 , wherein the peeling layer contains a vinyl acetate-vinylpyrrolidone copolymer as the vinyl resin.

14. The thermal transfer sheet according to claim 1 , wherein the thermocurable resin particle is at least one particle selected from the group consisting of a benzoguanamine-formaldehyde copolymer, a benzoguanamine-melamine-formaldehyde copolymer, and a melamine-formaldehyde copolymer.

Assignees

• Dainippon Printing Co Ltd

Inventors

• Imakura Yuzu
• Hirokawa Junko

Classifications

• B41M5/44 Primary

  characterised by the macromolecular compounds · CPC title

• Y10T428/24893

  including particulate material · CPC title

• B32B27/30

  comprising vinyl {(co)polymers; comprising acrylic (co)polymers} · CPC title

• B41M5/423 Primary

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

• B41M2205/38

  Intermediate layers; Layers between substrate and imaging layer · CPC title