Thermosensitive recording medium

Patent metadata

Field	Value
Publication number	US-11945249-B2
Application number	US-202017441059-A
Country	US
Kind code	B2
Filing date	Feb 25, 2020
Priority date	Mar 20, 2019
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

The present invention provides a thermosensitive recording medium having a high degree of water resistance and excellent surface qualities. The thermosensitive recording medium has a thermosensitive recording layer comprising a colorless or pale colored basic leuco dye and an electron accepting developing agent on a substrate, but does not have a protective layer on the thermosensitive recording layer, and the thermosensitive recording layer further comprises (i) a carboxy-modified polyvinyl alcohol as a binder, (ii) an epichlorohydrin resin and a modified polyamine/amide resin (excluding those contained in the category of epichlorohydrin resin) as crosslinking agents, and (iii) an acrylic resin with a glass transition temperature (Tg) of lower than or equal to 50 degree C. and a minimum film forming temperature (MFT) of higher than or equal to 40 degree C.

First claim

What is claimed is:

1. A thermosensitive recording medium having a thermosensitive recording layer comprising a colorless or pale colored basic leuco dye and an electron accepting developing agent on a substrate, but not having a protective layer on the thermosensitive recording layer, wherein the thermosensitive recording layer further comprises (i) a carboxy-modified polyvinyl alcohol as a binder, (ii) an epichlorohydrin resin and a modified polyamine/amide resin excluding those contained in the epichlorohydrin resin as crosslinking agents, and (iii) an acrylic resin with a glass transition temperature (Tg) of lower than or equal to 50 degree C. and a minimum film forming temperature (MFT) of higher than or equal to 40 degree C.

2. The thermosensitive recording medium of claim 1 , wherein the acrylic resin has a glass transition point (Tg) of 40 degree C. to 50 degree C.

3. The thermosensitive recording medium of claim 1 , wherein the minimum film-forming temperature (MFT) of the acrylic resin is 60 degree C. to 80 degree C.

4. The thermosensitive recording medium of claim 1 , wherein a content of methyl methacrylate (MMA) in the acrylic resin is 60% or more.

5. The thermosensitive recording medium of claim 1 , wherein the acrylic resin does not contain styrene as a monomer.

6. The thermosensitive recording medium of claim 1 , wherein the acrylic resin is a non-core shell type acrylic resin.

7. The thermosensitive recording medium of claim 1 , wherein the weight ratio of the carboxy-modified polyvinyl alcohol to the acrylic resin is 80/20 to 20/80.

8. The thermosensitive recording medium of claim 2 , wherein the minimum film-forming temperature (MFT) of the acrylic resin is 60 degree C. to 80 degree C.

9. The thermosensitive recording medium of claim 2 , wherein a content of methyl methacrylate (MMA) in the acrylic resin is 60% or more.

10. The thermosensitive recording medium of claim 2 , wherein the acrylic resin does not contain styrene as a monomer.

11. The thermosensitive recording medium of claim 2 , wherein the acrylic resin is a non-core shell type acrylic resin.

12. The thermosensitive recording medium of claim 2 , wherein the weight ratio of the carboxy-modified polyvinyl alcohol to the acrylic resin is 80/20 to 20/80.

13. The thermosensitive recording medium of claim 3 , wherein a content of methyl methacrylate (MMA) in the acrylic resin is 60% or more.

14. The thermosensitive recording medium of claim 3 , wherein the acrylic resin does not contain styrene as a monomer.

15. The thermosensitive recording medium of claim 3 , wherein the acrylic resin is a non-core shell type acrylic resin.

16. The thermosensitive recording medium of claim 3 , wherein the weight ratio of the carboxy-modified polyvinyl alcohol to the acrylic resin is 80/20 to 20/80.

17. The thermosensitive recording medium of claim 4 , wherein the acrylic resin does not contain styrene as a monomer.

18. The thermosensitive recording medium of claim 4 , wherein the acrylic resin is a non-core shell type acrylic resin.

19. The thermosensitive recording medium of claim 4 , wherein the weight ratio of the carboxy-modified polyvinyl alcohol to the acrylic resin is 80/20 to 20/80.

Assignees

• Jujo Paper Co Ltd

Inventors

• Kawasaki Kentaro
• Midorikawa Yoshimi
• Hirai Kenji

Classifications

• B41M5/3372 Primary

  Macromolecular compounds · CPC title

• B41M5/323 Primary

  Organic colour formers, e.g. leuco dyes · CPC title

• B41M2205/04

  Direct thermal recording [DTR] · CPC title

• B41M5/333

  Colour developing components therefor, e.g. acidic compounds · CPC title

• B41M5/337

  Additives; Binders {(B41M5/46 takes precedence)} · CPC title