# US 5,348,930 A · Heat sensitive recording material

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- Number: US 5,348,930 A
- Document ID: US5348930A
- Status: Granted
- Kind: A
- Application number: 08/042,109
- Filed: 1993-04-02
- Granted: 1994-09-20
- Earliest claimed: 1993-04-02
- Assignees: Nicca Chemical Co., Ltd.
- Inventors: Norio Kobayashi; Toshiaki Takahashi; Masahiro Makino; Masaaki Hosoda
- Web page: https://patentgrep.com/patent/US5348930A

## CPC

- B41M 5/3336: {Sulfur compounds, e.g. sulfones, sulfides, sulfonamides}
- B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P)

## Abstract

A heat sensitive recording material comprises a heat sensitive color forming layer containing a color former of a colorless or light color leuco dyestuff, a developer which develops color by reaction with the color former upon heating and is a mixture of 97 to 70 weight % of 2,4'-dihydroxydiphenylsulfone and 3 to 30 weight % of 4,4'-dihydroxydiphenylsulfone and a sensitizer. The heat sensitive color forming layer is coated on a support. The heat sensitive recording material has excellent color forming property by which sufficiently high concentration and sensitivity of the color forming are obtained and has excellent stability of the image with time.

## Claims

### Claim 1

A heat sensitive recording material comprising, as a coating on a support, a heat sensitive color forming layer containing a color former of colorless or light color leuco dyestuff, a developer which develops color by reaction with the color former upon heating and is a mixture of 97-70% by weight of 2,4'-dihydroxydiphenylsulfone and 3-30% by weight of 4,4'-dihydroxydiphenylsulfone and at least one sensitizer selected from the group consisting of p-benzyldiphenyl, di(p-methylbenzyl) oxalate, .beta.-benzyl-oxynaphthalene, 1,2-di(methylphenoxy)ethane, m-terphenyl, diphenylsulfone and phenyl 2,4,6-mesitylenesulfonate.

### Claim 2 (depends on 1)

The heat sensitive recording material of claim 1, wherein the developer is a mixture of 97 to 90 weight % of 2,4'-dihydroxydiphenylsulfone and 3 to 10 weight % of 4,4'-dihydroxydiphenylsulfone.

### Claim 3 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is p-benzyldiphenyl.

### Claim 4 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is di(p-methylbenzyl) oxalate.

### Claim 5 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is .beta.-benzyloxynaphthalene.

### Claim 6 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is 1,2-di(m-methylphenoxy)ethane.

### Claim 7 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is m-terphenyl.

### Claim 8 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is diphenylsulfone.

### Claim 9 (depends on 1)

The heat sensitive recording material of claim 1 wherein the sensitizer is phenyl 2,4,6-mesitylenesulfonate.

### Claim 10 (depends on 1)

The heat sensitive recording material of claim 1, wherein the sensitizer is present in an amount of 10-700 parts by weight based on 100 parts by weight of the color former.